KHBBBMMM 


THE   ESSENTIALS   OF   PSYCHOLOGY 


THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON  •    CHICAGO 
SAN   FRANCISCO 

MACMILLAN  &  CO.,  LIMITED 

LONDON    •    BOMBAY   •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  LTD. 


TORONTO 


THE 
ESSENTIALS  OF  PSYCHOLOGY 


BY 
W.   B.   PILLSBURY 

PROFESSOR   OF   PSYCHOLOGY,   UNIVERSITY  OF  MICHIGAN 


gorfe 

THE   MACMILLAN   COMPANY 
1913 

All  rights  reserved 


COPYRIGHT,  1911, 
BY  THE  MACMILLAN  COMPANY. 

Set  up  and  electrotyped.     Published  June,  1911.      Reprinted 
September,  October,  1911  ;  February,  May,  1919;  January,  1913. 


Xortoooft  tfrrsa 

J.  8.  Cnshlne  Co.  -  Berwick  &  Smith  Co. 
Norwood,  Mass.,  U.S.A. 


TO 

E.  C.  P. 


2052643 


PREFACE 

THE  aim  of  this  volume  is  to  present  clearly  the 
accepted  facts  of  psychology.  Throughout,  emphasis 
has  been  placed  upon  fact  rather  than  theory.  Where 
theories  conflict,  the  better  one  has  been  chosen,  the 
others  merely  neglected.  This  may  seem  dogmatic 
in  places,  but  in  a  text  dogmatism  is  preferable  to  con- 
fusion. The  point  of  view  is  on  the  whole  functional ; 
more  attention  is  given  to  what  mind  does  than  to  what 
it  is.  With  this  goes  an  emphasis  upon  the  outward 
manifestations  of  consciousness  and  upon  the  behaviour 
of  others  to  the  subordination  of  the  individual  con- 
sciousness. Nevertheless,  use  is  made  of  the  results 
of  structural  psychology  wherever  they  throw  light 
upon  function  or  are  interesting  for  themselves.  The 
position,  it  is  hoped,  combines  the  advantages  of  the 
rival  schools. 

The  content  of  a  text-book  in  psychology  is  suffi- 
ciently agreed  upon  to  require  no  comment.  The 
general  practice  has  been  followed  of  introducing  a 
brief  exposition  of  the  nervous  system  and  its  function. 
This  is  done  with  a  full  appreciation  that  it  is  no  part 
of  the  task  of  the  psychologist  to  teach  neurology,  but 
with  the  conviction  that  the  beginning  student  in  psy- 
chology is  not  likely  to  have  acquired  the  knowledge 
elsewhere.  In  this  treatment  as  little  detail  of  structure 
has  been  given  as  is  compatible  with  an  understanding 
vii 


Viii  PREFACE 

of  function.  Large  use  has  been  made  of  the  hypothe- 
sis of  the  synapse.  Its  convenience  in  explaining  habit 
and  association  outweighs  any  scruples  about  its  final 
position  in  physiology.  For  the  rest,  I  have  deviated 
from  traditional  usage  only  in  introducing  rather  more 
of  the  results  of  recent  experiment.  A  body  of  knowl- 
edge has  been  developing  in  connection  with  memory 
and  action  that  seems  ripe  for  embodiment  in  a  text. 
Similar  considerations  have  led  to  the  introduction  of 
chapters  on  fatigue  and  on  the  transfer  of  training. 

The  general  arrangement  followed  is  relatively  novel. 
It  consists  in  first  developing  a  few  simple  principles 
and  then  making  frequent  application  of  them  to  the 
more  complicated  processes.  Sensation,  habit,  reten- 
tion, and  selection  or  control  are  fundamental  and 
appear  repeatedly  in  mental  operations  of  all  kinds. 
When  they  are  once  understood,  it  is  only  necessary 
to  develop  their  applications  and  interconnections  to 
master  the  more  developed  operations.  The  method 
involves  much  repetition,  but  not  more  than  the  expe- 
rience of  the  writer  has  proved  necessary.  What  is  not 
understood  in  one  connection  is  made  clear  by  the  next 
application. 

My  obligations  to  psychological  writers  are  so  gen- 
eral and  so  apparent  as  to  need  no  special  acknowledg- 
ment. Dr.  Rowe  of  the  Central  Normal  School,  Mt. 
Pleasant,  Michigan,  has  read  the  manuscript  and  made 
many  suggestions.  Thanks  are  due  also  to  my  colleague, 
Dr.  Shepard,  for  help  at  many  points.  I  owe  most 
to  my  wife,  who  has  given  constant  advice  in  matters 
of  expression,  and  has  been  of  great  service  in  the 
mechanical  preparation  of  the  book. 


PREFACE  IX 

I  desire  also  to  express  my  thanks  to  authors  and 
publishers  for  permission  to  reproduce  illustrations. 
I  am  indebted  to  The  W.  B.  Saunders  Company  and 
Professor  Howell  for  figures  from  'The  Text-book  of 
Physiology '  and  the  '  American  Text-book  of  Physi- 
ology ' ;  to  Dr.  L.  F.  Barker  for  figures  from  his  '  Ner- 
vous System ' ;  to  Henry  Holt  and  Company  and 
Professor  Angell  for  cuts  from  his  *  Psychology ' ; 
to  Houghton  Miffiin  Company  and  Professor  Jastrow 
for  figures  from  '  Fact  and  Fable  in  Psychology ' ;  to 
The  Macmillan  Company  and  Professors  Titchener  and 
Calkins,  respectively,  for  figures  from  *  A  Text-book 
of  Psychology'  and  'A  First  Book  of  Psychology'; 
to  Professor  Swift  for  a  Curve  of  Learning,  and  to 
Professor  von  Frey  for  permission  to  adapt  his  Tem- 
perature Scale. 

ANN  ARBOR,  MICH., 
April  25,  1911. 


TABLE    OF   CONTENTS 


I.    INTRODUCTION I 

II.    THE  NERVOUS  SYSTEM 16 

III.  NEURAL  ACTION  IN   RELATION   TO  CONSCIOUSNESS 

AND  BEHAVIOUR   .......  46 

IV.  SENSATION  .  .......  60 

V.  SELECTION  AND  CONTROL  —  ATTENTION  .        .        .  104 

VI.     RETENTION  AND  ASSOCIATION 130 

VII.    PERCEPTION 156 

VIII.    MEMORY  AND  IMAGINATION 188 

IX.     REASONING .        .        .  216 

X.     INSTINCT 238 

XL     FEELING 258 

XII.    THE  EMOTIONS 272 

XIII.  ACTION  AND  WILL 284 

XIV.  WORK,  FATIGUE,  AND  SLEEP 315 

XV.  INTERRELATIONS  OF  MENTAL  FUNCTIONS         .        .  330 

XVI.    THE  SELF 343 


ESSENTIALS  OF  PSYCHOLOGY 


CHAPTER  I 

INTRODUCTION 

PSYCHOLOGY  is  traditionally  denned  as  the  science  of 
mind.  This  is  the  translation  of  the  two  Greek  words  from 
which '  psychology '  is  compounded.  The  definition  is  now 
open  to  many  objections.  The  most  important  of  these 
is  that  the  word '  mind '  has  in  the  course  of  long  use  taken 
on  many  meanings  and  implications  which  do  not  concern 
psychology  as  a  science.  Various  terms  have  been  sug- 
gested to  avoid  these  objections.  Psychology  has  been 
defined  as  the  'science  of  consciousness,'  or  as  the  'science 
of  experience  subjectively  regarded.'  Each  of  these 
definitions  has  advantages,  but  none  is  free  from  objec- 
tion. It  is  most  satisfactory  to  give  up  the  attempt  to 
find  a  single  word  that  will  designate  the  facts  covered 
by  psychology,  and  to  indicate  the  actual  phenomena 
that  it  studies,  —  the  evidences  of  mind.  First  of  these 
is  behaviour.  We  distinguish  a  man  in  the  full  possession 
of  his  senses  from  an  imbecile  by  the  character  of  his  acts. 
We  measure  the  intelligence  of  an  animal  by  its  accom- 
plishments. Mind  is  known  from  man's  activities.  Psy- 
chology may  be  most  satisfactorily  defined  as  the  science 
of  behaviour.  We  shall  discuss  human  behaviour. 


2  ESSENTIALS   OF   PSYCHOLOGY 

Man  may  be  treated  as  objectively  as  any  physical 
phenomenon.  He  may  be  regarded  only  with  reference 
to  what  he  does.  Viewed  in  this  way  the  end  of  our 
science  is  to  understand  human  action.  The  practical 
end  is  to  determine  upon  what  human  capacity  depends 
and,  in  the  light  of  this  knowledge,  to  discover  means  of 
increasing  man's  efficiency.  In  many  fields  of  industry 
it  is  becoming  more  and  more  evident  that  an  under- 
standing of  the  laws  of  human  efficiency  is  quite  as  im- 
portant as  a  knowledge  of  mechanical  laws,  that  it  is  quite 
as  important  to  know  what  a  man  can  do  in  a  given  time 
and  how  he  should  work  to  obtain  the  best  results  as  to 
know  the  laws  for  the  production  of  energy  in  boiler  and 
engine.  In  fact,  it  is  appreciated  in  many  industries  that 
further  progress  must  wait  upon  increased  knowledge  of 
the  human  instrument.  Psychology  is  concerned  only 
indirectly  with  these  practical  problems.  Science  always 
endeavours  to  understand  the  laws  of  nature  for  them- 
selves and  is  indifferent  to  the  applications  that  may  be 
made  of  them.  Psychology  is  interested  in  the  conditions 
of  learning  and  forgetting,  of  imagining  and  reasoning,  and 
in  the  methods  of  acquiring  skill  in  various  activities  with- 
out any  thought  of  the  use  that  may  be  made  of  the  know- 
ledge. It  is  probable,  however,  that  all  suggestions  for 
improving  the  efficiency  of  individuals  must  be  based  upon 
these  laws.  Indeed,  many  rules  have  already  been  de- 
veloped from  the  psychological  experiments  and  more  are 
foreshadowed  in  the  general  principles  now  established. 

If  psychology  is  to  be  defined  as  the  science  of  human 
behaviour,  the  term  'behaviour'  must  be  used  in  the 
very  widest  sense.  It  must  include  everything  from  the 


INTRODUCTION  3 

simplest  movements  of  walking  or  of  fingering  the  pen  to 
the  activities  involved  in  swaying  an  audience  by  speech 
or  in  carrying  to  completion  some  great  engineering  work. 
Certain  of  the  very  simplest  acts,  such  as  winking  and 
other  reflexes,  are  fairly  within  the  range  of  physiology. 
But  even  these  must  be  taken  into  consideration  by  psy- 
chology, because  the  most  complicated  act  can  be  under- 
stood only  when  analysed  into  its  components  which  are 
closely  related  to  reflexes.  Even  the  simplest  forms  of 
behaviour  must  be  studied  by  the  psychologist  if  he  is  to 
know  the  laws  that  govern  the  more  complicated  forms. 
No  form  of  human  behaviour,  from  the  simplest  to  the 
most  complex,  falls  outside  of  the  province  of  psychology. 
As  a  science  our  knowledge  of  human  behaviour  must  be 
organised  and  referred  to  a  system  of  general  principles. 
A  science  of  human  behaviour  cannot  be  limited  to  a 
series  of  aphorisms  or  chance  observations  about  man. 
'Perseverance  wins  success'  is  related  to  the  psychology 
of  conduct  in  very  much  the  same  way  that '  an  east  wind 
brings  rain '  is  related  to  the  science  of  meteorology.  Each 
statement  embodies  the  results  of  numerous  observations, 
but  it  has  no  close  connection  with  other  facts  or  general 
laws.  In  a  science  these  observations  must  be  related  to 
other  bits  of  knowledge  and  the  whole  organised  into  a 
consistent  system  that  shall  harmonise  with  the  results 
of  other  sciences.  Scientific  laws  are  based  on  more 
carefully  chosen  data  and  in  consequence  possess  wider 
validity  and  are  less  likely  to  be  vitiated  by  popular 
prejudice  or  ill-founded  tradition.  They  give  each  par- 
ticular fact  a  perspective  and  make  it  easy  to  recall  and 
to  use  each  new  observation. 


4  ESSENTIALS   OF   PSYCHOLOGY 

Even  if  we  regard  the  understanding  of  human  behaviour 
as  the  ultimate  end  of  psychology,  consciousness  must 
still  play  a  very  important  part  in  our  science.  By  con- 
sciousness we  mean  a  man's  awareness  of  his  own  acts  and 
their  antecedents.  While  the  reader  might  at  this  mo- 
ment be  observed  by  a  friend  to  hold  the  book  and  move 
the  eyes  by  jerks  across  the  page  with  an  occasional  frown 
as  a  difficult  sentence  is  met,  the  reader  himself  is  aware 
of  the  sense  of  the  material  that  is  read,  and  thinks  in 
some  part  the  ideas  that  are  intended  by  the  writer. 
The  one  appreciates  the  behaviour,  the  other  conscious- 
ness. In  this  case  behaviour  is  the  immediate  outcome 
of  consciousness  and  can  only  be  understood  through  it. 
The  frown  can  be  explained  from  the  hesitation  in  getting 
the  meaning  of  a  sentence,  and  that  is  evident  to  the 
reader  alone.  While  many  kinds  of  activity  are  best 
known  from  the  inside,  others  may  be  as  well  known  from 
the  outside.  Thus  the  capacity  of  an  individual  for 
assimilating  the  material  of  this  chapter  may  be  deter- 
mined as  well  by  the  instructor  who  assigns  it  and  quizzes 
on  it  as  by  the  student.  This  is  particularly  true  if  the 
reading  is  done  under  the  observation  of  the  teacher. 
The  reasons  for  the  differences  in  capacity  to  learn  and 
repeat  could  be  known  either  by  the  individual  himself  or 
by  the  observer  only  through  long  study  of  the  individual 
in  the  light  of  earlier  training  and  habits  of  work.  In  gen- 
eral, then,  consciousness  is  always  an  important  means  of 
knowing  behaviour.  How  important  depends  upon  the 
sort  of  behaviour.  The  more  complicated  forms  of  be- 
haviour can  be  understood  only  through  consciousness ; 
the  simpler  may  be  understood  from  without.  Con- 


INTRODUCTION  5 

sciousness  must  have  a  very  large  place  in  psychology,  not 
only  because  action  may  usually  be  explained  through  it, 
but  also  because  of  its  own  interest.  There  is  nothing 
more  interesting  to  the  ordinary  individual  than  the  work- 
ings of  his  own  mind.  This  interest  alone  would  justify 
the  existence  of  the  science.  Consciousness  is  at  once  an 
important  means  of  understanding  behaviour  and  an  in- 
teresting object  of  investigation  for  itself.  Consciousness 
and  behaviour  are  closely  related ;  consciousness  in  others 
is  known  only  through  behaviour,  behaviour  in  ourselves 
and  ultimately  in  others  is  known  only  through  conscious- 
ness. If  one  is  made  the  end,  the  other  must  be  the 
means;  if  either  is  understood  in  its  completeness,  the 
other  will  also  be  known.  They  are  the  inside  and  outside 
of  the  same  organism.  At  the  present  stage  in  the  de- 
velopment of  psychology,  it  seems  best  to  subordinate 
consciousness  to  behaviour.  Psychology  is  the  science  of 
behaviour.  Behaviour  is  to  be  studied  through  the  con- 
sciousness of  the  individual  and  by  external  observation. 
Mind,  Consciousness,  and  Mental  Process.  —  Before 
attempting  any  discussion  of  mental  states  it  is  necessary 
to  define  certain  of  the  terms  that  are  to  be  used.  Viewed 
from  within,  psychology  seeks  to  explain  the  experiences 
of  the  individual  as  they  run  their  course,  —  to  under- 
stand the  various  external  impressions,  memories,  im- 
aginings, and  so  on  that  together  constitute  the  mental 
life.  Any  one  of  the  states  that  may  be  regarded  as  de- 
tached from  the  mass  for  separate  consideration  is  desig- 
nated a  mental  process.  Your  idea  of  this  book  as  you 
read  it  is  a  mental  process,  your  memory  of  reading  the 
book  yesterday  or  of  the  assignment  for  study  is  a  mental 


6  ESSENTIALS    OF   PSYCHOLOGY 

process  as  is  the  flitting  thought  that  you  would  much 
rather  be  out  for  a  walk  than  reading.  Consciousness  is 
the  term  ordinarily  used  to  designate  the  sum  total  of 
mental  processes  at  any  moment.  Thus,  the  perception 
of  the  book,  the  background  of  tactual  and  organic  sensa- 
tions that  are  receiving  no  particular  attention  at  the 
moment,  the  vague  emotional  dissatisfaction  that  you  are 
kept  indoors  on  a  pleasant  day,  and  many  other  more  or 
less  definite  mental  processes  combine  to  constitute  your 
consciousness  at  this  moment.  Consciousness  is  also  used 
less  definitely  for  any  sort  of  awareness,  however  great  its 
duration,  but  this  is  not  generally  recognised  as  the  tech- 
nical meaning.  Mind  is  the  word  that  is  ascribed  to  the 
entire  series  of  conscious  states  of  an  individual  from  birth 
to  death.  It  is  the  most  inclusive  of  the  series  of  terms 
and  covers  all  processes,  active  and  passive.  Experience 
is  used  to  designate  practically  the  same  mass  of  states, 
but  it  is  a  little  more  passive  in  its  implications.  All  of 
these  terms  apply  to  the  description  of  behaviour  as  ob- 
served from  within,  the  mental  antecedents  and  accom- 
paniments of  behaviour.  The  description  of  behaviour  as 
it  presents  itself  to  the  outside  observer  needs  only  the 
vocabulary  of  popular  speech  and  requires  no  preliminary 
comment  or  definition. 

The  Methods  of  Psychology.  —  As  has  been  said,  be- 
haviour can  be  studied  in  two  ways ;  by  observation  of 
another's  acts  and  by  observation  of  one's  own  conscious 
states.  Observation  of  another,  or  what  in  psychology  is 
known  as  observation,  requires  no  special  comment  as  a 
method.  In  all  essential  respects  it  follows  the  rules  of 
observation  that  are  common  to  all  of  the  sciences.  Self- 


INTRODUCTION  7 

observation,  known  technically  as  introspection,  seems 
at  first  sight  to  offer  more  difficulties  and  to  require  more 
safeguards.  The  question  has  been  raised  whether  in- 
trospection is  possible  at  all.  The  doubt  arises  from  the 
assumption  that  the  very  observation  of  a  mental  state 
changes  that  state.  One  does  not  have  the  same  mental 
state  when  questioning  how  one  knows  that  the  approach- 
ing footsteps  are  Smith's,  as  when  one  interprets  the 
sounds  to  mean  that  Smith  is  coming.  One  cannot  at 
the  same  moment  wonder  what  one  is  doing  and  do  it  to 
the  best  advantage.  This  objection  proves  to  be  less 
serious  in  practice  than  in  theory.  All  mental  states  per- 
sist for  a  little  time  unchanged  and  it  is  possible  to  observe 
tfiem  during  this  persistence.  One  does  not  observe  the 
mental  state  at  the  time  it  is  happening,  but  examines  it  a 
moment  later  in  memory.  Observation  in  memory  is  ac- 
curate and  does  not  alter  the  process  investigated.  Ob- 
servation in  any  natural  science  requires  the  same  reliance 
on  momentary  memory.  One  cannot  make  an  observa- 
tion and  record  it  at  the  same  time.  If  one  tried,  mis- 
takes would  be  made.  The  reading  is  taken  and  held  hi 
memory  until  recorded,  and  then  still  later  it  is  inter- 
preted or  used  in  the  explanation  of  related  facts.  In- 
trospection is  no  more  difficult  or  uncertain  than  is  ob- 
servation of  external  phenomena. 

Experiment.  —  Within  the  last  generation  both  intro- 
spection and  observation  have  come  to  be  largely  carried 
on  under  experimental  conditions  and  with  the  aid  of 
instruments  of  precision.  Experiment  has  aided  both  ob- 
servation and  introspection  by  making  it  possible  to  con- 
trol accurately  the  conditions  and  antecedents  of  mental 


8  ESSENTIALS   OF   PSYCHOLOGY 

operations.  It  is  possible  now  to  remove  from  distracting 
stimuli  the  individual  who  is  introspecting  or  being  ob- 
served and  to  measure  accurately  the  stimuli  that  are  per- 
mitted to  affect  him.  The  results  obtained  when  obser- 
vation is  assisted  by  instruments  are  even  more  striking. 
It  is  a  commonplace  that  a  man  who  is  embarrassed  will 
blush.  Delicate  physiological  instruments  used  in  the 
psychological  laboratory  show  that  the  blush  is  only  a 
heightened  effect  of  the  changes  in  circulation  that  take 
place  in  all  parts  of  the  body  in  connection  with  almost 
all  mental  processes.  Similarly  it  was  first  observed  with 
the  unaided  eye  that  the  eyes  moved  by  jumps  during  read- 
ing. Later  it  was  found  possible  to  photograph  the  move- 
ments of  the  eyes,  and  these  results  brought  out  important 
points  that  could  not  have  been  attained  otherwise.  In- 
trospection has  been  aided  principally  by  recording  the 
times  that  elapse  between  different  parts  of  a  mental  op- 
eration. The  times  required  have  been  combined  and  the 
results  emphasised  relations  that  were  noticed  in  intro- 
spection. While  experiment  is  only  a  means  of  increas- 
ing the  accuracy  of  observation  and  introspection,  it  has 
through  its  wide  application  made  possible  important 
advances  in  nearly  every  field  of  psychology.  To  its  great 
benefit  psychology  has  become  an  experimental  science. 
But  momentary  introspection  and  observation  com- 
bined, even  with  all  the  help  that  maybe  had  from  experi- 
ment, do  not  exhaustively  explain  behaviour  or  conscious- 
ness. The  observer  sees  the  occasion  for  action  and  notes 
the  response ;  the  actor  sees  the  object  and  feels  the  re- 
sponse, but  neither  knows  what  happens  in  between  nor 
appreciates  fully  the  conditions  of  the  act.  For  example, 


INTRODUCTION  9 

a  wasp  approaches,  the  man  draws  back  or  strikes.  The 
observer  notes  the  occasion  for 'the  movement  and  the 
movement  itself,  but  nothing  more.  The  man  attacked 
sees  the  wasp  and  knows  that  he  is  moving  or  has  moved, 
but  nothing  more.  Neither  can  know  why  the  movement 
takes  place.  One  sees  the  stimulus  vanish  into  the  phys- 
ical organism  and  movement  result;  the  other  sees  the 
insect,  moves,  and  all  the  time  is  perturbed  by  an  emotion, 
but  neither  can  absolutely  foresee  the  movement  that 
results,  neither  knows  why  it  results.  These  more  funda- 
mental explanations  may  be  supplied  in  part  on  the  basis 
of  present  knowledge.  Two  elements  must  be  taken  into 
consideration  in  the  interpretation,  —  the  character  and 
nature  of  the  action  of  the  nervous  system,  and  the  past 
life  and  native  endowment  of  the  individual.  One  can 
understand  what  intervenes  between  the  first  excitation 
and  the  movement  that  results  only  if  one  can  trace  the 
course  of  connection  through  the  nervous  system.  The 
earlier  history  of  the  individual  and  of  the  race  plays  a  very 
large  part  in  the  determination  of  all  sorts  of  behaviour. 
The  man's  responses  will  differ  according  to  the  amount 
and  nature  of  his  experience  with  wasps.  The  influence 
of  earlier  experiences  can  be  traced  in  many  more  subtle 
ways  in  the  interpretation  of  any  mental  phenomenon. 
Both  the  nervous  system  and  the  effects  of  earlier  life  upon 
the  acts  of  the  individual  can  be  known  only  through 
observation  and  introspection  controlled  and  recorded, 
together  with  much  experiment  and  reflection  upon  the 
connections  of  present  with  past  activities.  Human  be- 
haviour, then,  can  be  understood  by  careful,  long  con- 
tinued observation  of  man  in  action  from  the  inside  and 


10  ESSENTIALS   OF   PSYCHOLOGY 

from  the  outside,  and  by  relating  the  results  of  these  ob- 
servations to  the  earlier  experiences  of  the  individual  and 
to  the  facts  concerning  the  nature  and  action  of  the  ner- 
vous system  that  have  been  accumulated  by  the  anato- 
mist and  the  physiologist. 

Relation  of  Psychology  to  Other  Sciences.  —  The 
relations  of  psychology  to  the  other  sciences  are  particu- 
larly close  and  important.  The  biological  sciences  shade 
over  into  psychology  so  gradually  that  it  is  not  always 
possible  to  decide  whether  a  problem  belongs  to  psy- 
chology or  to  one  of  the  biological  sciences.  The  sciences 
that  explain  the  nature  and  action  of  the  human  body, 
the  sciences  of  anatomy  and  physiology,  verge  gradually 
over  into  psychology.  One  can  understand  behaviour 
only  if  one  knows  something  of  the  organism  that  acts,  of 
the  sense  organs  that  receive  the  impression  from  with- 
out, of  the  muscles  that  produce  the  actions,  and  of  the 
nervous  system  that  connects  them.  From  the  outside 
one  can  understand  man's  behaviour  most  fully  and 
easily  by  comparing  it  with  the  behaviour  of  animals  and 
tracing  the  gradual  development  of  man's  action  in  con- 
nection with  the  simpler  forms  of  animal  behaviour.  Ex- 
perimental biology  gradually  shades  over  into  experimen- 
tal psychology.  The  biologist  has  recently  been  devoting 
himself  very  largely  to  the  problems  of  animal  behaviour. 
The  light  cast  upon  human  conduct  by  these  experiments 
is  only  less  important  than  that  cast  upon  the  actions  of 
animals  themselves.  Still  more  general  results  of  biologi- 
cal sciences  have  been  profoundly  important  for  the  ex- 
planation of  human  consciousness.  The  very  general  ac- 
ceptance in  recent  times  of  the  doctrine  of  evolution  has 


INTRODUCTION  1 1 

forced  us  to  read  the  story  of  mind  in  the  light  of  the  de- 
velopment of  the  human  organism  from  the  lower  forms  of 
life.  The  result  is  a  very  much  fuller  understanding  of 
many  of  the  more  fundamental  phases  of  human  activity. 
All  of  the  physical  sciences  furnish  some  material  for  the 
psychologist,  since  the  sense  processes  can  be  understood 
only  in  connection  with  the  physical  forces  that  act  upon 
the  organism. 

The  Related  Sciences  of  Man.  —  In  addition  to  the 
sciences  from  which  it  receives  material  and  methods, 
psychology  has  come  into  a  position  where  it  may  offer 
help  to  many  sciences.  If  psychology  can  give  informa- 
tion concerning  human  behaviour,  it  is  evident  that  all 
the  human  and  social  sciences  may  look  to  it  for  aid  in  the 
solution  of  their  problems.  Sociology,  or  the  study  of 
man  in  the  group,  evidently  must  found  its  results  upon  a 
study  of  the  individual.  In  less  degree  history,  when  it 
seeks  to  trace  connections  between  its  observed  facts, 
must  look  to  psychology  for  its  fundamental  princi- 
ples. Economics,  too,  works  with  psychological  materials. 
Its  fundamental  problems  are  essentially  psychological. 
Values  and  human  needs  are  largely  mental.  It  must  be 
said,  however,  that  psychology  is  least  well  developed  in 
the  fields  where  it  would  be  most  helpful  to  the  his- 
torian and  to  the  economist.  Last  of  all,  the  relations  of 
psychology  to  philosophy  are  very  numerous  and  are  those 
of  mutual  helpfulness.  Psychology  was  the  last  of  the 
sciences  to  separate  from  philosophy,  the  parent  of  all  of 
the  sciences,  and  the  bond  is  still  very  close.  The  history 
of  psychology  is  still  very  largely  a  part  of  the  history  of 
philosophy.  The  results  of  psychology  are  in  large  part 


12  ESSENTIALS   OF   PSYCHOLOGY 

the  foundation  of  philosophy,  and  on  the  other  hand 
philosophy  supplies  the  psychologist  with  general  prin- 
ciples and  sets  very  many  of  his  problems  for  him. 

Of  the  immediately  practical  subjects,  education  has 
probably  made  the  largest  demands  upon  the  results  of 
our  science.  Learning  and  teaching  are  both  psychologi- 
cal operations.  When  any  real  attempt  to  understand 
either  is  made,  education  becomes  an  application  of  psy- 
chology. This  is  more  and  more  appreciated  in  the  mod- 
ern schools,  and  in  them  psychology  and  education  are 
coming  closer  and  closer  together.  The  psychologist  is 
paying  more  attention  to  the  problems  of  the  educator, 
and  the  modern  educational  theorists  are  making  more  use 
of  the  results  of  psychological  investigations.  But  the  ap- 
plications of  psychology  need  not  be  confined  to  education. 
With  the  advance  of  knowledge  all  who  have  to  deal  with 
man  will  look  to  the  psychologist  to  ever  increase  the 
knowledge  that  may  be  put  at  his  disposal.  The  physi- 
cian and  the  lawyer,  the  advertiser  and  the  clergyman,  are 
all  dealing  in  one  way  or  another  with  psychological  prob- 
lems. To  the  physician  and  the  advertiser  psychology 
has  already  given  appreciable  aid  and  it  should  be  in  a 
position  at  no  distant  day  to  offer  help  to  the  others.  Too 
much  of  practical  value  is  not  to  be  expected  from  the 
science.  In  all  of  these  fields  there  is  a  great  difference 
between  principles  and  practice.  Often  the  rules  that 
grow  from  daily  practice  are  in  advance  of  scientific  prin- 
ciples. Science  serves  but  to  explain  the  truth  of  the 
practical  precept.  Theory  does  not  always  lag  behind, 
and  one  can  already  see  places  in  which  psychological 
results  point  the  way  to  improvement  in  practice.  As 


INTRODUCTION  13 

a  rule,  however,  established  arts  are  more  grateful  for  con- 
firmation of  the  established  custom  than  for  the  sugges- 
tion of  improvements.  This  incomplete  list  of  the  rela- 
tions of  psychology  may  suffice  to  indicate  how  closely 
psychology  is  bound  up  with  other  fields  of  human  know- 
ledge. Any  science  that  tells  us  anything  of  the  nature 
of  the  physical  universe  or  of  the  nature  of  the  living 
organism  will  throw  some  light  upon  the  problems  of  psy- 
chology. On  the  other  hand,  any  science  that  deals  in  any 
way  with  human  conduct,  or  that  is  dependent  in  any  way 
upon  human  capacity  (and  what  science  is  not?),  can 
draw  with  profit  upon  the  results  of  psychology.  Either 
as  creditors  or  debtors,  all  the  sciences  stand  in  some 
relation  to  psychology,  the  science  of  human  behaviour. 
Divisions  of  Psychology.  —  Each  of  the  sciences  that  fur- 
nish material  for  psychology  has  given  rise  to  a  different 
sort  of  psychology,  or  at  least  to  a  different  name  for  a 
psychological  work.  Psychophysics  grew  out  of  an  at- 
tempt by  Fechner  to  determine  the  quantitative  relations 
between  the  physical  stimulus  and  the  intensity  of  the 
mental  state.  Physiological  psychology  is  the  name 
Wundt  gives  to  his  work,  that  has  for  its  primary  object 
the  explanation  of  the  relation  between  mental  states  and 
the  bodily  organism.  Each  of  these  treatments  grew  be- 
yond its  original  scope  to  cover  the  entire  field  of  psychol- 
ogy. The  name  indicates  nothing  more  than  the  attitude 
that  is  taken  toward  the  subject.  Other  branches  of  the 
subject  are  marked  off  by  the  part  of  the  material  of  be- 
haviour that  is  discussed.  Genetic  psychology  treats 
of  the  development  of  behaviour.  The  behaviour  of 
animals  has  given  rise  to  a  flourishing  science  and  in  the 


14  ESSENTIALS    OF   PSYCHOLOGY 

last  few  years  has  made  much  progress.  Child  study  has 
made  numerous  contributions  to  the  more  theoretical 
problems.  Each  has  thrown  some  light  upon  the  nature 
of  adult  human  behaviour,  as  well  as  collected  many  facts 
in  its  own  field.  Abnormal  psychology,  the  study  of  ab- 
normal and  imperfect  individuals,  has  also  been  a  rich  field 
for  the  psychologist  and  has  given  many  important  results. 
Each  of  these  partial  sciences  may  be  considered  by  us 
only  so  far  as  it  throws  light  on  the  behaviour  of  the  adult 
normal  man.  A  few  years  ago  it  was  customary  to  clas- 
sify psychological  systems  according  to  the  methods  of 
investigation.  There  was  a  rational  psychology,  an  em- 
pirical psychology,  an  introspective  psychology,  and  an 
experimental  psychology.  Now  it  is  seen  that  no  science 
can  be  developed  by  one  of  these  methods  alone,  and  all 
are  used  by  any  psychologist  worthy  of  the  name.  At 
the  most  it  can  now  be  said  that  there  is  an  empirical  and 
a  rational  method  in  psychology,  a  method  of  introspec- 
tion and  a  method  of  observation,  both  aided  by  experi- 
ment. The  results  of  each  method  should  be  the  same  if 
the  methods  are  adequate.  And  as  a  matter  of  fact  the 
results  are  the  same  except  that  one  method  will  be  ade- 
quate for  one  problem,  another  for  another.  All  the  so- 
called  branches  of  psychology,  then,  are  closely  related  to 
the  central  science  and  at  the  most  designate  merely 
different  fields  for  observation,  or  the  preference  of 
writers  for  different  methods. 

Our  problem  is  to  understand  behaviour,  and  to  inves- 
tigate consciousness  as  the  immediate  antecedent  and 
condition  of  behaviour.  To  understand  either  conscious- 
ness or  behaviour  it  is  necessary  to  know  something  of 


INTRODUCTION  15 

the  character  and  action  of  the  nervous  system.  As  has 
been  said,  all  knowledge  of  the  world  comes  to  conscious- 
ness through  the  nervous  system  and  all  expressions  of 
consciousness  in  action  are  rendered  possible  by  the  ner- 
vous system.  This  is  not  psychology  but  is  a  necessary 
prerequisite  for  psychology.  The  psychological  problem 
proper  begins  with  an  analysis  of  the  elements  of  conscious- 
ness, both  structural  and  functional.  The  structural 
elements  are  found  in  the  qualities  received  through  the 
senses,  and  the  elements  that  are  retained  and  revived  in 
memory.  The  primary  function  is  the  capacity  for  selec- 
tion that  chooses  the  elements,  both  sensations  and  mem- 
ories, that  shall  enter  consciousness.  To  these  may  be 
added  a  third  principle,  that  all  elementary  structures  tend 
to  arouse  movements  and  that  these  movements  are  con- 
trolled by  sensations.  The  fundamental  facts  and  activi- 
ties of  consciousness  and  behaviour  serve  as  a  basis  for  the 
explanation  of  all  of  the  more  complicated  concrete  mental 
processes  and  operations.  The  analysis  of  consciousness 
and  of  behaviour  consists,  first,  in  determining  the  ele- 
mentary states  or  activities,  and  then  of  seeing  how  they 
interact  and  unite  in  the  constitution  and  control  of  the 
more  complicated  activities.  The  various  partial  prob- 
lems will  be  taken  up  in  the  order  named :  first,  a  brief 
statement  of  the  facts  of  nervous  physiology  that  have  a 
bearing  upon  psychology;  second,  an  analysis  of  the  facts 
of  consciousness  and  behaviour  to  discover  the  elementary 
components,  and  third,  a  study  of  the  more  complicated 
activities  in  the  light  of  these  simplest  forms. 


CHAPTER  II 
THE   NERVOUS   SYSTEM 

BEHAVIOUR  must  be  explained  in  large  part  by  the  action 
of  the  nervous  system.  It  does  not  follow  that  the  action 
of  the  brain  or  of  the  nervous  system  is  open  to  observa- 
tion. On  the  contrary,  one  knows  nothing  under  any  cir- 
cumstances of  the  nerves  or  of  nerve-cells.  All  that  is 
known  is  consciousness.  The  parts  that  act  are  alto- 
gether hidden,  the  effects  alone  are  known.  So  com- 
pletely is  this  true  that  even  Aristotle,  the  most  acute 
observer  of  antiquity,  had  no  suspicion  that  the  brain  had 
anything  to  do  with  mental  processes.  He  held  that  the 
brain  was  merely  a  gland  for  the  secretion  of  tears.  Its 
only  function  in  thinking  was  to  cool  the  animal  spirits 
that  originated  in  the  heart  and  circulated  through  the 
brain. 

Dependence  of  Consciousness  on  the  Nervous  Sys- 
tem. —  If  one  cannot  observe  the  nervous  system  directly 
during  its  action,  one  may  ask  what  right  we  have  to 
assert  that  consciousness  is  related  to  it.  Two  facts  bear 
most  strongly  in  proof  of  the  relation.  The  first  is  that 
behaviour  increases  in  complexity  with  increase  in  the 
complexity  of  the  nervous  system.  In  the  rudimentary 
organisms  no  nervous  system  can  be  distinguished.  The 
same  protoplasm  that  cares  for  the  nutrition  of  the  body 

16 


THE   NERVOUS    SYSTEM  If 

also  receives  the  stimulus  and  contracts.  All  parts  are 
alike  and  each  does  all  things  that  are  necessary  to  its  own 
welfare.  The  movements  are  correspondingly  simple  and 


FIG.  i.  —  Shows  the  development  of  pyramidal  cells  from  the  cerebrum  of 
vertebrates.  (A-D)  neurones  from  an  ascending  series  of  vertebrates,  (a-e)  the 
stages  in  the  development  of  cells  in  man.  (4)  frog ;  (B)  lizard  ;  (C)  rat ;  (D) 
man.  (a)  neuroblast  without  dendrites ;  (b)  commencing  dendrites ;  (c) 
dendrites  further  developed ;  (d)  first  appearance  of  collaterals ;  (e)  further 
development  of  collaterals  and  dendrites.  (From  Howell :  '  Text-book  of 
Physiology,'  Fig.  £3,  after  Ramon  y  Cajal.) 

the  organism  poorly  adjusted  to  its  surroundings.  As  we 
go  higher,  nerve-cells  are  present,  but  they  are  few  and 
the  connections  are  relatively  scant.  Behaviour  is  more 
complicated  as  the  nervous  system  is  better  developed. 
In  the  lower  vertebrates,  a  reptile  for  example,  the  ner- 


1 8  ESSENTIALS   OF   PSYCHOLOGY 

vous  system  is  larger,  the  parts  are  more  highly  developed, 
and  the  connections  between  the  elements  are  more  nu- 
merous. The  movements  that  may  be  made  are  also 
more  numerous,  and  they  are  more  closely  adapted  to  the 
environment.  The  animal  is  better  equipped  to  live  and 
to  act.  The  climax  of  evolution,  both  in  behaviour  and 
in  the  structure  and  connections  of  the  nervous  system,  is 
found  in  man.  In  short,  mind  or  behaviour  develops  in 
the  same  degree  as  the  nervous  system,  whether  we  meas- 
ure the  development  of  the  nervous  system  by  the  charac- 
ter of  the  nerve  unit,  by  the  nature  of  the  connection  be- 
tween nerve  units,  or,  with  few  exceptions,  by  the  relative 
mass  of  nervous  tissue  to  body  weight. 

Defects  of  Brain  and  Mental  Defects.  —  The  evidence 
from  pathology  for  the  close  relation  of  mind  and  body  is 
even  more  striking.  An  injury  to  the  head  that  in  any 
other  part  of  the  organism  would  produce  but  slight  dis- 
turbance of  consciousness  may  destroy  consciousness. 
If  we  turn  to  a  closer  study,  it  is  found  that  injury  to  any 
part  of  the  brain  will  produce  a  corresponding  disturbance 
in  the  mental  state  and  in  behaviour.  Injury  to  small 
portions  of  the  brain  gives  rise  to  paralyses  of  small  groups 
of  muscles,  causes  the  loss  of  some  sense  or  impairs  forms 
of  behaviour,  while  other  sorts  of  consciousness  or  forms  of 
behaviour  will  be  unaffected.  Injury  to  any  portion  of 
the  nervous  system  will  impair  some  capacity  in  some 
degree.  Conversely  if  behaviour  or  consciousness  is  af- 
fected, some  change  in  the  nervous  system  is  usually 
found.  These  two  facts  taken  in  connection  with  what 
we  know  of  physiology,  and  what  can  be  seen  directly  of 
the  action  of  nerve  in  connection  with  muscle  in  the 


THE   NERVOUS    SYSTEM  1 9 

lower-  organisms,  suffice  to  make  indisputable  the  very 
intimate  relation  between  mind  and  brain. 

Development  of  the  Nervous  System.  —  It  is  perhaps 
easiest  to  understand  the  nervous  system  if  we  consider 
it  in  connection  with  the  development  of  the  animal 
organism  from  the  lowest  forms.  All  organisms  can  be 
regarded  as  developed  from  the  simplest  of  unicellular 
organisms.  The  amceba  may  be  regarded  as  the  type  of 
the  original  simplest  form.  The  amceba  is  a  single  cell. 
This  cell  is  at  once  nervous  system  and  muscle,  mouth 
and  stomach.  When  it  moves,  the  cell  contracts  or  ex- 
pands or  changes  its  form  as  a  whole.  When  it  is  stimu- 
lated, the  impression  is  received  by  part  of  the  organism 
and  the  result  is  to  call  out  a  contraction  in  the  same 
and  in  neighbouring  parts.  When  the  stimulus  is  a  food 
particle,  it  induces  a  movement  of  the  organism  or  part 
of  it  toward  the  particle  and  about  it  until  the  particle  is 
entirely  surrounded.  Then  the  same  tissue  that  received 
the  stimulus  apparently  acts  as  a  digestive  organ  to  as- 
similate the  morsel.  The  original  cell  is  thus  possessed  in 
some  degree  of  the  capacities  of  all  parts  of  the  human  or 
higher  organism. 

The  development  of  the  higher  organisms  may  be  re- 
garded as  dependent  upon  the  union  of  many  of  these  sim- 
plest cells  into  a  single  whole  or  colony.  Whether  or  not 
separate  cells  ever  did  combine  in  this  way  is  a  matter  of 
indifference.  It  at  least  illustrates  the  nature  of  the  rela- 
tion of  simple  cells  to  the  more  complicated  organism. 
The  different  cells  take  on  different  functions  and,  in 
many  cases,  different  forms.  No  matter  how  changed, 
each  cell  of  the  body  is  regarded  as  a  separate  organism 


20  ESSENTIALS   OF   PSYCHOLOGY 

that  has  lost  something  of  its  individuality,  but  is  never- 
theless descended  directly  from  the  independent  amoeba- 
like  prototype.  The  bone  cells  perhaps  are  most  removed 
from  the  original ;  the  corpuscles  of  the  blood,  the  white 
corpuscles  in  particular,  have  changed  hardly  at  all. 
Next  to  the  blood  corpuscles  the  nerve-cells  probably  have 
been  least  changed  from  the  original  type.  Except  for  its 
dependence  upon  the  other  members  of  the  colony  for  its 
food,  and  for  the  fact  that  the  other  cells  serve  to  give  it 
form,  a  nerve-cell  is  still  independent.  The  function  of 
the  nerve-cells  in  the  colony  may  be  regarded  metaphori- 
cally as  protective  and  connective.  They  compel  the 
different  parts  to  act  together,  and  on  the  right  occasion 
they  enable  the  parts  to  respond  to  the  external  world. 
The  nervous  system  enables  the  organism  to  act  as  a  unit 
and  not  as  a  mass  of  separate  organisms. 

The  Divisions  of  the  Nervous  System.  — As  one  looks 
at  the  central  nervous  system  of  man,  one  can  observe 
three  fairly  distinct  structures.  The  largest  is  the  cere- 
brum, enclosed  by  the  skull.  This  is  a  mass  roughly 
like  a  sphere  much  corrugated  on  its  surface  by  irregular 
folds.  Two  of  the  fissures  are  most  prominent.  One,  the 
median  fissure,  serves  to  divide  the  cerebrum  into  two 
parts  throughout  more  than  half  its  height.  It  is  in  the 
approximate  centre  of  the  mass.  This  division  makes  it 
customary  to  regard  the  halves  as  distinct,  and  hence  we 
speak  of  the  two  hemispheres.  The  other  is  on.  either 
side  of  the  hemispheres,  is  not  so  deep,  and  is  known  as  the 
fissure  of  Sylvius.  Slanting  upward  from  the  lower  front 
part  of  the  brain,  it  will  be  seen  from  the  diagram  to  con- 
stitute a  prominent  landmark.  Below  the  cerebrum  at 


THE   NERVOUS   SYSTEM 


21 


Cer, 


FIG.  2.  —  Shows  the  nervous  system  as  a  whole.  The  figure  on  the  left  represents 
the  relation  of  the  nervous  system  to  the  body  as  a  whole,  that  on  the  right  the 
nervous  system  exposed  and  seen  from  the  front.  (Cer.)  the  cerebrum ;  (Cb.)  the 
cerebellum ;  (Sp.  C.)  the  spinal  cord ;  (P)  the  pons ;  (M)  the  medulla.  The 
other  letters  in  the  right-hand  figure  designate  nerve  trunks  going  to  the  cen- 
tral nervous  system.  (From  Angell :  '  Psychology,' Fig.  12.) 


22  ESSENTIALS    OF   PSYCHOLOGY 

the  back  are  large  masses  of  nerve-cells  and  connecting 
masses  of  white  fibre.  Among  them  are  the  cerebellum 
at  the  back,  the  pons  in  front,  and  the  medulla  below. 
Each  can  be  made  out.  The  other  structures  in  this 
region  are  too  numerous  to  mention,  and  the  action  is 
too  complicated  to  discuss  within  the  limits  of  so  brief  a 
sketch.  Below  is  the  cord.  The  whole  mass  is  con- 
tained in  a  bony  box.  The  cerebrum,  the  cerebellum, 
and  most  of  the  lower  ganglia  are  within  the  skull ;  the 
cord,  within  the  spinal  column.  Outside  of  the  cord 
but  within  the  spinal  column  are  the  spinal  ganglia  that 
are  composed  of  the  neurones  that  receive  impressions 
from  the  skin  and  muscles. 

Each  of  these  masses  is  composed  of  grey  and  white 
matter.  The  grey  matter  is  made  up  of  cell  bodies,  the 
white  matter  of  nerve  fibres.  In  the  cord  the  grey 
matter  is  in  the  centre,  where  it  constitutes  a  butter- 
fly-shaped central  core.  The  butterfly  shape  is  well 
marked  in  the  sections,  as  can  be  seen  in  the  diagrams. 
In  the  cerebrum  and  the  cerebellum  the  cell  bodies  are 
for  the  most  part  upon  the  cortex  (bark),  the  outermost 
layer ;  the  white  connecting  parts  are  within  and  below. 
In  the  medulla  and  general  midbrain  region,  no  law  for 
the  distribution  of  white  and  grey  matter  can  be  stated  in 
a  few  words.  Strands  of  fibres  are  interspersed  with 
masses  of  cell  bodies,  —  here  one,  there  the  other,  is  on 
the  surface. 

The  Growth  of  the  Nervous  System.— The  architec- 
ture of  the  different  parts  can  be  understood  most  clearly 
from  a  study  of  the  development  of  the  system.  In  the 
early  stages  of  the  embryo  the  central  nervous  system 


THE    NERVOUS    SYSTEM  23 

is  but  a  groove  in  the  outer  layer  of  the  mass.  This  groove 
gradually  becomes  deeper,  and  the  tops  of  the  sides  ap- 
proach until  they  grow  together  to  form  a  tube.  The 
different  parts  of  the  entire  nervous  system  grow  from 
different  parts  of  the  wall  of  the  tube.  The  original  hollow 
persists  to  the  adult  stage  and  is  modified  by  the  changes 
in  the  shape  of  the  wall.  First  the  tube  is  pinched  in 
three  places,  which  later  subdivide  into  five.  The 
hemispheres  grow  out  at  the  front,  or  head,  and  grow  up 
and  back  until  they  cover  the  other  vesicles.  The  struc- 
tures below  the  cerebrum  develop  by  the  thickening  of 
the  walls  of  the  four  lower  vesicles,  or  swellings  of  the 
tube.  The  connections  of  the  parts  retain  in  the  adult 
many  traces  of  the  earlier  stages  of  development.  The 
relation  of  the  parts  was  not  well  understood  until  the 
development  of  the  system  was  known. 

The  Elements  of  the  Nervous  System.  —  We  may 
represent  the  nervous  system  most  clearly  as  itself  a 
colony  of  some  eleven  thousand  million  amceba-like  organ- 
isms crowded  together  for  the  most  part  within  the  bony 
wall  of  the  skull  and  spinal  column  with  prolongations  ex- 
tending to  all  parts  of  the  organism.  The  unit  of  the 
nervous  system  is  the  neurone.  Each  is  connected  with 
numerous  other  units,  and  also  at  innumerable  points 
stands  in  close  functional  relations  to  the  other  cells  of  the 
body.  To  understand  the  action  of  the  nervous  system 
we  must  learn  to  know  (i)  the  character  of  the  single  unit 
and  (2)  the  connections  the  units  make  with  each  other 
and  with  other  parts  of  the  body.  The  neurone  consists 
of  a  cell  body  and  two  sorts  of  prolongations  or  processes, 
the  axone  or  axis  cylinder,  and  the  dendrites.  The  axone 


24  ESSENTIALS    OF   PSYCHOLOGY 

is  a  long,  hairlike  extension  that  may  reach  more  than 
half  the  length  of  the  body.  Most  nerves  in  the  periphery 
of  the  body  are  groups  of  axones.  The  axone  ordinarily 
terminates  in  a  mass  of  treelike  branches  called  the  end- 
brush.  The  dendrites  are  similar  to  the  end-brush. 
They  are  made  up  of  a  number  of  branches  of  the  cell 


FIG.  3.  —  A  group  of  human  nerve-cells  drawn  to  the  same  scale,  (a)  small 
cell  from  ventral  horn  of  the  cord ;  (b)  cell  from  Clarke's  column,  thoracic 
cord ;  (c)  small  nerve-cell  from  tip  of  dorsal  horn,  thoracic  cord ;  (d)  spinal 
ganglion  cell,  cervical  root ;  (e)  three  granules  from  cerebellum ;  (/)  Purkinje 
cell  from  cerebellum ;  (g)  small  pyramidal  cell  from  second  layer  of  central 
gyri  of  cortex  ;  (h)  giant  pyramidal  cell  from  the  same  region.  (From  Don- 
aldson, in  the  '  Amer.  Text-book  of  Physiology,'  after  Adolf  Meyer.) 

protoplasm  and  are  usually  relatively  short.  The  end- 
brush  of  one  cell  is  ordinarily  in  contact  with,  or  very  near, 
the  dendrites  of  other  cells.  The  two  together  are  some- 
times called  the  arborization  of  the  cells.  The  points  of 
contact  are  also  designated  as  the  synapses.  The  form  of 
the  neurone  varies  greatly.  In  some  cases  the  cell  body 
is  approximately  round  and  relatively  smooth.  In 


THE   NERVOUS   SYSTEM  .  25 

other  cases  it  is  more  spindle-shaped,  in  others  again  the 
surface  is  much  broken  by  the  processes.  In  certain 
parts  of  the  cortex  the  cells  are  almost  pyramidal  in  their 
general  shape,  with  processes  at  each  of  the  angles.  In 
the  spinal  ganglia  many  of  the  cells  that  receive  and 
transmit  the  impressions  from  the  skin  and  muscles  have 
dendrites  and  axones  combined  in  a  single  process.  The 
division  is  only  recognizable  some  little  distance  from  the 


FIG.  4.  —  Longitudinal  and  transverse  sections  of  medulated  nerve  fibre  from  the 
sciatic  nerve  of  frog.  The  myelin  sheath  is  shown  in  black,  the  central  proto- 
plasm shows  its  fibrous  structure.  (From  Barker,  Fig.  80,  after  Biedermann.) 

cell  body.  All  of  these  forms  are  to  be  regarded  as  depar- 
tures from  the  type.  But  the  character  of  the  cell  has  no 
demonstrable  relation  to  the  function.  The  number  of 
dendrites  and  the  number  of  branches  of  the  axone  de- 
termine the  number  of  connections  that  the  cell  may 
make;  the  form  of  the  cell  depends  upon  the  number 
and  position  of  the  processes,  but  so  far  as  is  known 
that  is  the  only  relation  that  holds  between  form  and 
function. 

The  Parts  of  the  Neurone.  —  The  neurone  is  a  vital 
unit.  The  processes  receive  nourishment  only  from  the 
cell  body,  and  when  cut  off  from  the  cell  body,  they  die. 
The  substance  or  protoplasm  of  the  cell  body  is  continu- 


26  ESSENTIALS   OF   PSYCHOLOGY 

ous  with  the  protoplasm  of  the  processes.  The  central 
protoplasm  of  the  neurone  shows  no  important  differences 
in  the  character  of  its  parts.  The  only  points  worthy  of 
mention  are:  (i)  the  sheaths  of  the  axone,  and  (2)  the 
nucleus  of  the  cell  body.  Two  sheaths  may  be  distin- 
guished, an  inner  or  myelin  sheath,  and  an  outer,  the 
neurilemma.  The  inner  sheath  is  found  in  all  except  a 
few  fibres  in  the  higher  centres,  the  second  is  present  out- 
side of  the  central  nervous  system.  In  the  sympathetic 
system  the  outer  sheath  is  usually  the  immediate  cover- 
ing of  the  protoplasm.  The  myelin  sheath  seems  to  have 
some  importance  for  the  function  of  the  neurone,  but  just 
what  has  not  been  made  out.  The  nucleus  of  the  cell 
stands  in  some  vital  relation  to  the  action  of  the  cell.  In 
fatigue  the  nucleus  has  been  shown  to  become  smaller 
and  irregular  in  outline.  Its  exact  function,  however, 
has  not  been  determined.  Recently  small  fibrils  have 
been  traced  within  the  substance  of  the  nerve-cell,  but 
their  function  also  is  not  known. 

The  Transmission  of  the  Impulse  within  the  Neurone. 
—  What  goes  on  in  the  neurone  when  it  acts  has  not 
been  definitely  determined.  Theories  have  varied  at 
different  periods  from  assuming  that  some  fluid  was  trans- 
mitted through  the  nerves  or  that  some  wave  was  propa- 
gated along  the  substance  of  the  nerve,  to  the  assumption 
that  the  action  was  electrical  in  character.  To-day  the 
most  usually  accepted  theory  is  that  some  form  of  chemi- 
cal change  spreads  through  the  neurone  as  it  acts.  This 
hypothesis  is  supported  by  several  facts,  (i)  The  rate  of 
propagation,  about  one  to  two  hundred  metres  a  second, 
is  altogether  too  slow  for  electrical  transmission,  but  is 


THE   NERVOUS    SYSTEM  27 

within  the  limits  of  chemical  action.  (2)  The  action  of 
the  nerve-cell  is  accompanied  by  electrical  phenomena. 
Whenever  a  nerve  is  stimulated,  an  electric  current  passes 
from  the  cut  end  of  the  nerve  to  the  uninjured  sheath. 
If  a  frog's  nerve  be  dissected  out  and  one  end  be  connected 
to  a  point  on  the  neurilemma  through  a  delicate  galva- 
nometer, the  galvanometer  will  indicate  the  passage  of  an 
electric  current  when  the  nerve  is  stimulated  in  any  way. 
Similar  electric  currents  are  induced,  as  is  well  known,  by 
the  chemical  action  in  a  battery.  (3)  The  action  of  nerve- 
cells  frees  certain  chemical  substances,  products  of  decom- 
position, that  are  removed  by  the  blood.  These  three 
facts  point  to  the  assumption  that  action  of  the  nerves 
is  due  to  some  chemical  change.  This  assumption  fits  in 
with  most  of  our  detailed  knowledge  of  the  action  of  the 
nervous  system.  Our  picture  of  the  propagation  of  an 
excitation  through  a  neurone  is  that  it  corresponds  to  the 
spread  of  chemical  processes  through  its  substance  in  very 
much  the  same  way  that  a  spark  runs  along  a  train  of  gun- 
powder. In  the  nerve  the  burning  is  but  partial,  and 
the  materials  used  up  are  constantly  replenished  from 
the  blood,  but  both  processes  are  oxidations,  — in  each  the 
destruction  spreads  from  part  to  part  within  the  mass. 
It  is  important  to  note,  too,  that  the  change  is  transmitted 
only  in  one  direction.  The  stimulus  is  always  received 
by  the  dendrite  and  is  transmitted  along  the  axone  to  the 
end-brush.  It  never  runs  in  the  reverse  direction.  One 
apparent  exception  may  be  noted.  The  cells  in  the  spinal 
ganglia  receive  the  impressions  from  the  skin  by  a  long 
process  that  extends  to  the  surface  of  the  body  and  is  in  its 
structure  similar  to  an  axone.  We  may  either  call  this 


28  ESSENTIALS    OF   PSYCHOLOGY 

a  peculiar  form  of  dendrite  or  regard  it  as  an  exception  to 
the  law  that  the  axis  cylinder  does  not  receive,  but  always 
transmits,  the  impulse.  Which  of  the  alternatives  for  dis- 
posing of  the  exception  may  be  adopted  is  not  as  yet  a 
matter  of  common  agreement. 

Our  picture  of  the  nervous  system  is  of  a  mass  of  ten 
thousand  millions  or  so  of  these  minute  organisms  en- 
closed within  a  bony  case,  the  skull  and  the  spinal  column. 
Each  cell  is  independent  from  the  others  in  its  structure, 
but  the  terminals  are  in  contact  with  each  other.  In  the 
mass  we  ordinarily  distinguish  three  sorts  of  neurones,  — 
the  sensory,  the  motor,  and  the  associating.  The  differ- 
ence is  one  of  connection  and  function  rather  than  of 
structure.  The  sensory  are  receiving  neurones;  the 
motor  send  impressions  out  to  the  muscles,  while  the  asso- 
ciating neurones  serve  to  bring  sensory  and  motor  neu- 
rones into  connection.  As  the  sensory  neurones  always 
lead  towards  the  centre,  they  are  sometimes  called  centrip- 
etal or  afferent,  and  for  a  similar  reason  the  motor  neu- 
rones are  the  centrifugal  or  efferent  elements.  There  is 
no  constant  difference  in  structure  between  sensory  and 
motor  neurones.  The  difference  in  function  is  probably 
largely  dependent  upon  the  connections.  It  is  also  usual 
in  the  nervous  system  to  distinguish  white  matter  and 
grey  matter.  The  distinction  is  drawn  from  the  fact  that 
when  one  looks  with  the  naked  eye,  the  masses  of  cell 
bodies  have  a  greyish  colour,  masses  of  axones  are  white. 
The  white  matter  is  made  up  largely  of  axones,  the  pro- 
longations of  cell  bodies ;  the  grey  matter  is  a  mass  of  cell 
bodies.  These  masses  of  cell  bodies  are  also  known  as 
ganglia  (sing,  ganglion).  Neither  can  be  understood 


THE   NERVOUS    SYSTEM  2Q 

apart  from  the  other.  The  white  matter  is  merely  a 
bundle  of  transmitting  fibres,  the  grey  matter  nothing 
more  than  a  mass  of  central  cells,  but  every  fibre  of  the 
white  matter  is  a  prolongation  of  some  cell  body  and  can- 
not live  without  it. 

The  Connections  of  Neurones.  — The  action  of  the  neu- 
rone is  dependent  upon  its  connection.  A  cell  never  acts 
alone.  It  is  always  a  link  in  a  reflex  arc.  All  action  of 
animal  or  man  is  excited  by  some  stimulus  in  the  external 
world,  and  every  sensory  excitation  ends  in  some  move- 
ment. The  reflex  arc  in  the  nervous  system  always  has 
its  origin  in  a  sense-organ  and  ends  in  a  muscle.  In  be- 
tween there  may  be  any  number  of  associatory  cells,  but 
these  beginning  and  end  structures  must  always  be  pres- 
ent. The  problem  of  action  from  the  side  of  nerve  physi- 
ology is  one  of  determining  the  paths  of  connection  of  the 
sensory  and  motor  neurones.  The  course  of  transmission 
from  neurone  to  neurone  is  determined  by  the  openness 
of  the  paths.  These  connections  are  in  part  fully  formed 
in  the  organism  at  birth,  in  part  they  are  acquired  through 
the  activities  of  the  animal  during  life.  Of  these  paths 
of  connection  we  may  recognise  three  levels:  first,  the 
direct  connections  of  the  cord ;  second,  the  paths  through 
the  lower  brain,  the  medulla,  and  general  midbrain 
region;  and  third,  the  more  indirect  and  complicated 
lines  of  connection  in  the  cerebral  cortex.  Each  is  to  be 
looked  upon  as  a  path  between  sense-organ  and  muscle. 
They  are  different  ways  by  which  the  sensory  impression 
may  be  transmitted  to  the  muscle:  they  are  different 
primarily  in  the  directness  with  which  the  transfer  is 
made ;  the  higher  paths  permit  more  connections  and 


30  ESSENTIALS   OF   PSYCHOLOGY 

make  possible  the  cooperation  of  a  greater  number  of 
sensory  impulses  in  the  control  of  movement. 


FIG.  5.  —  Showing  the  connections  between  cord  and  brain.  (G)  a  spinal  gan- 
glion cell  that  receives  impressions  from  the  sensory  ending  (D)  and  transmits 
a  central  impulse  over  (c).  The  path  bifurcates  at  (e),one  connection  enters 
the  central  grey  and  would  serve  to  conduct  reflexes  to  motor  neurones  that 
are  not  shown,  the  other  ascends  to  the  cortex,  giving  off  many  collaterals. 
Shows  also  the  descending  path  from  the  cortex  to  the  cord  and  the  motor 
neurones  of  the  anterior  horn  with  connections  to  muscls.  (From  Barker,  Fig. 
206,  after  Ramon  y  Cajal.) 


THE   NERVOUS    SYSTEM  31 

The  Action  of  the  Cord.  —  In  the  cord  impressions  from 
the  skin  and  from  internal  structures  are  carried  across 
to  the  muscles  of  limbs  and  trunk.  Through  it  appropriate 
responses  are  made  to  stimuli  of  various  sorts  on  the  skin. 
Drawing  back  the  hand  when  burned  is  primarily  due 
to  the  nervous  connections  that  are  made  in  the  cord. 
The  simplest  reflexes  of  the  cord  involve  two  neurones 
only.  The  end  organ  in  the  skin  is  connected  with  the 
dendrite  of  the  T-shaped  cell  in  the  spinal  ganglion,  the 
axone  of  that  cell  extends  into  the  butterfly-like  section 
of  grey  matter  in  the  cord,  and  the  end-brush  comes  in 
contact  with  the  dendrite  of  a  cell  on  the  anterior  side  of 
the  cord.  This  motor  cell  in  its  turn  sends  out  an  axis- 
cylinder  to  a  muscle.  The  chemical  change  induced  by 
the  physical  stimulus  travels  to  the  cell  body,  thence  to 
the  end-brush  or  synapse,  where  it  excites  an  impulse 
in  the  efferent  neurone  that  travels  down  to  the  muscle. 
The  chemical  change  is  transferred  at  that  point  from 
nerve  to  muscle  and  excites  the  chemical  change  involved 
in  the  muscular  contraction.  The  diagram  shows  that 
the  spinal  cord  consists  of  a  mass  of  white  fibres  which 
surround  a  core  of  grey  matter.  Here  are  found  the  cell 
bodies  of  the  motor  nerves,  and  the  associating  or  con- 
necting neurones.  The  fibres  of  the  surrounding  white 
matter  are  almost  exclusively  axones  of  sensory  cells  in  the 
spinal  ganglia  and  in  the  central  grey,  or  are  axones  of 
motor  neurones  in  the  higher  centres  of  the  cortex  or  mid- 
brain.  The  sensory  fibres  are  found  in  the  posterior  and 
in  the  lateral  columns.  The  motor  fibres  are  found  on 
the  side  and  in  front. 

The  Paths  in  the  Cord.  —  If  the  central  grey  may  be  re- 


32  ESSENTIALS   OF   PSYCHOLOGY 

garded  as  the  transferring  station,  the  surrounding  white 
constitutes  the  transmitting  paths  by  which  the  cortex 
and  higher  centres  in  general  are  connected  with  the  world 
outside.  The  sensory  tracts  bring  impressions  hi  from 
the  periphery  and  transmit  them  to  the  cerebrum.  The 
pyramidal  tracts  serve,  on  the  other  hand,  to  connect  the 
upper  tracts  with  motor  cells  in  the  cord,  and  thus  with 
the  muscles  of  the  lower  parts  of  the  body.  Not  only  do 
these  outer  fibre  layers  connect  the  upper  portion  of  the 
nervous  system  with  sense-organ  and  muscle,  but  they 
also  connect  the  different  levels  of  the  cord  with  each  other. 
A  sensory  impulse  not  only  excites  muscles  that  have 
their  cells  at  the  same  level  in  the  cord,  but  it  excites 
groups  of  muscles  at  different  levels  above  and  below. 
If  we  return  to  consider  the  simple  reflexes,  we  find  that 
the  sensory  stimulus  may  spread  not  merely  to  the  single 
motor  neurone  or  group  of  motor  neurones  at  the  same 
level,  but  it  may  make  connections  with  neurones  that  lie 
higher  and  lower  in  the  cord.  More  frequently  it  may 
extend  to  neurones  lying  in  the  opposite  side  of  the  cord 
and  produce  movements  of  members  on  the  other  side  of 
the  body.  If  one  destroy  the  brain  of  a  frog  or,  by  pith- 
ing, cut  the  cord  off  from  the  upper  nervous  system,  it  will 
'  be  seen  that  all  of  these  reflexes  may  still  be  called  out  by 
stimuli.  If  a  bit  of  paper  moistened  with  acid  be  placed 
upon  the  left  foot  of  a  frog,  the  foot  will  be  drawn  up.  If 
now  the  foot  be  held  so  that  it  cannot  be  moved,  it  will  be 
found  that  the  other  is  brought  over  to  remove  the  stimu- 
lus. If  this  is  not  successful,  the  muscles  of  the  forelegs 
and  trunk  will  contract  and  the  contractions  will  continue 
until  the  stimulus  is  removed  or  the  neurones  exhausted. 


THE   NERVOUS    SYSTEM 


33 


The  first  movement  (of  the  leg  that  is  stimulated)  is  due 
to  the  transfer  of  the  stimulus  to  the  motor  cell  or  cells  on 
the  same  side  of  the  cord.  When  the  foot  is  held  and  the 
stimulus  grows  strong  enough,  the  impulse  is  transmitted 
to  the  group  of  neurones  on  the  opposite  side  of  the  cord, 
and  muscles  of  the  right  leg  are  contracted.  When  the 
excitation  becomes  still  stronger,  the  discharge  spreads 
to  neurones  higher  up,  and  the  muscles  of  the  trunk  and 
the  upper  members  are  made  to  contract. 

Action  of  the  Synapse.  —  Since  there  are  evidently 
many  possible  lines  of  transmission,  the  question  natu- 
rally arises,  what  decides  which  of  the  many  paths  shall  be 
followed?  The  answer  is  found  in  a  recent  theory  that 
the  course  of  the  impulse  is  decided  at  the  point  of  con- 
nection between  neurone  and  neurone,  the  synapse.  The 


FIG.  6.  —  Shows  a  synapse  from  the  optic  lobe  of  a  chick.     (From '  Amer.  Text- 
book of  Physiology,'  Fig.  76,  after  Van  Gehuchten.) 

end-brush  of  the  receiving  neurone  is  in  contact  with 
the  dendrites  of  several  motor  neurones.  Each  of  these 
points  of  contact  or  synapses  has  a  different  resistance. 
The  path  to  muscles  of  the  same  leg  opens  most  easily; 
next  in  degree  of  openness  is  the  synapse  to  dendrites  of 
the  motor  neurone  that  controls  the  muscles  of  the  other 
leg,  while  the  synapse  that  connects  with  the  upper  mus- 


34  ESSENTIALS   OF   PSYCHOLOGY 

cles  of  the  trunk  opens  with  still  greater  difficulty.  The 
lines  of  discharge  depend  primarily  upon  the  openness  of 
the  synapses.  In  these  lowest  reflexes  the  ease  of  trans- 
mission depends  upon  the  character  of  the  synapses  as 
they  are  determined  in  the  individual  at  birth,  and  thus 
the  responses  are  prepared  in  advance  of  any  experience 
by  the  nature  of  the  nervous  system.  When  the  sensory 
excitation  is  weak,  only  the  best-developed  connections 
are  opened.  As  the  impulse  becomes  stronger,  more  and 
more  difficult  synapses  will  be  crossed,  and  the  motor 
discharge  will  become  more  and  more  diffuse. 

Reflexes  of  the  Second  Level. — At  the  second  level 
of  reflexes  the  same  general  laws  hold.  The  possibilities 
of  connection  are,  however,  very  much  more  numerous. 
Many  senses  contribute  impressions  and  the  muscles  over 
which  the  discharge  may  take  place  now  include  all  of  the 
muscles  of  the  body  instead  of  the  muscles  of  trunk 
and  limbs  only.  The  synapses  for  the  reflexes  of  this  level 
are  in  the  region  of  the  central  nervous  system  between 
the  top  of  the  cord  and  the  cortex.  The  anatomy  of  this 
region  is  too  complicated  to  be  described  within  our  limits, 
but  the  connections  are  made  in  the  numerous  accumula- 
tions of  cell  bodies  found  in  the  structures  of  the  medulla, 
midbrain,  and  on  up  to  the  lower  ganglia  of  the  cerebrum. 
Wherever  the  synapses  may  be  located,  we  may  dis- 
tinguish two  general  groups  of  connections.  First  each 
stimulus  tends  to  excite  certain  movements  immediately 
and  directly.  Thus  in  the  eye,  when  a  ray  of  light  falls 
upon  the  retina,  the  pupil  at  once  contracts.  This  move- 
ment is  called  out  by  the  sensory  stimulus  that  is  trans- 
mitted to  one  of  the  lower  centres  for  vision.  There  the 


THE   NERVOUS   SYSTEM  35 

motor  neurone  connected  with  the  muscles  is  excited  and 
the  pupil  contracts.  The  visual  impressions,  too,  excite  and 
control  the  movements  of  the  trunk  and  limbs  through  the 
motor  tracts  in  the  cord.  A  frog,  for  example,  that  has  had 
its  hemispheres  removed  will  avoid  obstacles  in  swimming 
or  hopping  and  will  give  other  evidences  that  its  move- 
ments are  guided  by  sight.  In  man  the  lower  neurones 
are  not  so  independent  of  the  cortex,  and  it  is  difficult  to 
demonstrate  that  they  can  act  alone.  The  functions  of 
these  structures  at  the  second  level,  in  what  is  usually 
called  the  midbrain  and  hindbrain,  are :  (i)  to  serve  as 
reflex  centres  by  which  the  senses  at  this  level  may  be 
connected  with  muscles  of  the  head ;  (2)  to  connect  the 
special  sense-organs  of  the  'head  with  the  motor  neurones 
of  the  cord,  and  so  with  the  muscles  of  trunk  and  limbs; 
and  (3)  to  connect  the  cortex  with  the  sense-organs  and 
with  the  muscles.  It  is  probable  that  all  the  sense- 
organs  are  represented  in  the  midbrain  by  neurones,  and 
that  in  every  case  the  impulse  from  a  sense-organ  is 
transferred  from  one  neurone  to  another  in  some  ganglion 
in  this  region.  The  mechanism  of  the  reflexes  is  the 
same  as  in  the  cord.  The  only  difference  is  that  the 
sources  of  excitation  are  more  numerous  and  the  pos- 
sibilities of  connection  are  greater. 

Action  of  Cortex.  —  By  far  the  most  important  divi- 
sion of  the  nervous  system  is  the  cerebrum.  In  man  the 
cerebrum  is  the  largest  of  the  nervous  structures,  con- 
stituting rather  more  than  half  of  the  total  nervous  system. 
It  is  also  the  part  of  the  nervous  system  most  closely  re- 
lated to  consciousness.  In  fact,  it  is  very  doubtful  if  any 
consciousness  at  all  accompanies  the  action  of  any  other 


36  ESSENTIALS   OF   PSYCHOLOGY 

portion  of  the  nervous  system.  Its  structure  and  func- 
tions are  very  complex,  but  our  guiding  principles 
still  suffice  to  explain  its  action.  It,  too,  is  made  up  of 
neurones  in  various  connections,  and  the  neurones  act  to 
transfer  sensory  impressions  to  motor  neurones,  and  so  to 
excite  muscles.  The  only  differences  are :  (i)  that  the 
possibilities  of  connection  are  vastly  greater,  and  (2) 
that  impressions  received  at  an  earlier  period  in  the  life 
of  the  individual  play  a  larger  part  in  controlling  the 
courses  of  the  sensori-motor  connections  than  they  do  in 
any  of  the  lower  centres.  In  consequence  the  processes 
that  intervene  between  stimulus  and  response  may  be  re- 
garded as  much  more  important  here  than  they  are  in 
any  of  the  reflexes  already  considered. 

Localization  of  Cortical  Functions.  —  We  must  dis- 
tinguish three  sorts  of  areas  or  regions  in  the  cortex.  Cer- 
tain areas  receive  the  impressions  from  the  outside  world 
and  are  known  as  the  sensory  regions.  Others  send  out 
impulses  to  the  muscles  and  are  known  in  consequence 
as  the  motor  regions.  The  rest  of  the  cortex  serves  to 
connect  the  sensory  and  motor  areas  and  constitutes  what 


FIG.  7.  —  Localization  of  cerebral  function.  The  lower  figure  shows  the  outer 
surface  of  the  right  hemisphere  ;  the  upper,  the  mesial  surface  ak.  the  left  hemi- 
sphere. In  both  figures  the  motor  areas  are  marked  by  horizontal  shading,  the 
sensory  by  vertical  shading,  while  the  associatory  areas  are  unshaded.  The 
doubtful  or  partially  sensory  or  motor  regions  are  indicated  by  dots.  (S)  is 
opposite  the  fissure  of  Sylvius;  (R)  above  the  fissure  of  Rolando.  (M)  is 
above  the  motor  region ;  (C)  above  the  cutaneous  and  kinaesthetic  area.  (V) 
indicates  the  visual  region ;  (O)  is  below  the  olfactory  area.  The  auditory 
region  is  just  below  the  fissure  of  Sylvius,  above  (H).  (FA)  designates  the 
frontal,  (PA)  parietal,  and  (TA)  the  temporal  association  centres.  There 
is  some  evidence  that  the  dotted  regions  about  the  sensory  and  motor  areas  are 
areas  in  which  particular  associations  are  formed  with  them.  The  diagram 
embodies  the  results  of  A.  W.  Campbell,  but  has  been  modified  in  one  or  two 
respects  to  agree  with  the  results  of  Flechsig  and  Gushing. 


THE   NERVOUS   SYSTEM 

c 


37 


TA 


See  opposite  page. 


38  ESSENTIALS   OF   PSYCHOLOGY 

are  known  as  the  association  areas.  The  first  two  are 
often  grouped  together  as  the  projection  areas,  since 
they  represent  regions  of  the  body  in  very  much  the  same 
way  that  parts  of  the  screen  may  be  said  to  represent  the 
slide  when  a  picture  is  thrown  upon  it  by  the  projection 
lantern.  The  relation  between  these  areas  and  the  sense- 
organ  and  muscle  is  very  close.  The  motor  region  is  easier 
to  demonstrate.  If  the  brain  of  a  man  be  exposed  for  an 
operation  and  the  motor  area  be  stimulated  electrically, 
some  muscle  of  the  body  will  respond  and  the  same  muscle 
or  group  of  muscles  will  always  respond  provided  the  same 
region  be  stimulated  in  the  same  degree.  The  areas  that 
correspond  to  the  different  muscles  are  sufficiently  well 
known  to  permit  a  decision  as  to  what  part  of  the  brain 
is  defective  in  case  some  group  of  muscles  be  paralysed. 
The  motor  area  of  the  brain  is  shown  in  the  diagram.  It 
lies  just  in  front  of  the  central  fissure,  the  fissure  of 
Rolando,  and  extends  upward  from  near  the  fissure  of  Syl- 
vius to  the  median  fissure  and  over  to  the  mesial  surface 
of  the  hemisphere.  As  is  generally  the  case  in  the  upper 
part  of  the  nervous  system,  the  right  brain  contains  the 
motor  centres  for  the  left  half  of  the  body  and  vice  versa. 
Sensory  Areas.  —  The  sensory  regions  are  scattered 
and  are  not  so  certainly  localized  as  the  motor  regions. 
The  part  of  the  cortex  connected  with  the  eye  is  in  the 
back  of  the  brain,  the  occipital  region.  The  part  that 
may  certainly  be  ascribed  to  vision  is  In  the  cuneus,  a 
wedge-shaped  convolution  on  the  mesial  surface.  It  is 
marked  in  the  diagram.  The  auditory  region  is  in  the 
temporal  lobe,  just  below  the  fissure  of  Sylvius  near  its 
junction  with  the  central  fissure.  The  sensations  from 


THE   NERVOUS    SYSTEM  39 

skin  and  muscle  are  received  in  the  region  just  behind  the 
central  fissure  and  are  distributed  in  very  much  the  same 
way  as  the  motor  connections  in  front  of  them.  Smell  is 
less  certainly  localized,  but  is  probably  on  the  mesial  sur- 
face, as  indicated  in  the  diagram.  Taste  may  be  near 
it,  but  the  localization  is  hardly  more  than  conjecture  at 
the  present  stage  of  knowledge. 

Association  Areas.  —  It  will  be  noticed  that  after  all 
the  regions  with  known  relations  to  sensation  and  move- 
ment are  enumerated,  the  greater  part  of  the  cortex  is 
left  without  assigned  function.  It  is  the  contention  of 
Flechsig,  now  generally  accepted,  that  the  remaining  por- 
tions of  the  brain  have  as  their  function  to  make  cross 
connections  between  the  sensory  and  the  motor  regions, 
to  unite  sensory  with  motor,  and  sensory  with  sensory 
areas.  For  example,  the  axone  from  a  cell  body  in  the 
optic  region  will  extend  to  the  intervening  association 
region  and  there  come  into  contact  with  the  dendrites  of 
numerous  association  neurones,  each  of  which  in  its  turn 
will  connect  with  other  sensory  or  motor  neurones,  or 
with  pther  association  neurones.  Each  intervening  asso- 
ciation neurone  will  increase  the  connections  that  a  sen- 
sory neurone  may  make,  and  so  increase  the  possible 
responses  that  the  same  stimulus  may  call  out. 

Action  of  the  Cortex  during  Speech.  —  If  we  turn  from 
structure  to  function,  we  find  that  the  nervous  excitation 
that  is  transmitted  from  the  sense-organ  to  the  sensory 
cells  in  the  cortex  must  sooner  or  later  find  its  way  to  a 
motor  neurone.  In  some  cases  the  motor  cell  that  is 
affected  is  in  the  same  region  of  the  brain.  Thus  move- 
ments of  the  eye  maybe  excited  by  stimulating  the  oc- 


40  ESSENTIALS    OF   PSYCHOLOGY 

cipital  lobes,  and  it  is  probable  that  movements  of  the 
eyes  on  visual  stimulation  may  have  a  path  in  the  cortex 
that  does  not  extend  beyond  the  optic  region  in  its  wider 
extent.  More  characteristic,  however,  are  the  inter- 
connections that  control  the  movements  involved  in 
speech.  These  are  of  interest  because  the  disturbances  of 
speech  were  among  the  earliest  to  receive  an  explanation. 
In  ordinary  repetition  of  spoken  words,  the  excitation  is 
transmitted  from  the  ear  by  way  of  a  lower  centre  to  the 
auditory  region,  thence  along  the  axone  of  a  sensory  neu- 
rone to  an  association  neurone  in  the  Island  of  Reil  (the 
bottom  of  the  fissure  of  Sylvius)  and  from  there  to  the 
motor  area  for  speech  in  the  lower  Rolandic  region.  Here 
the  end-brush  of  the  association  neurone  comes  into  func- 
tional union  with  the  dendrites  of  a  motor  neurone.  The 
axones  of  the  motor  neurone  end  through  the  mediation  of 
other  neurones  in  the  muscles  of  the  vocal  organs  and  the 
sound  is  repeated.  That  this  is  the  approximate  course 
of  the  nervous  impulse  we  know  from  a  comparison  of  the 
defects  of  speech  with  the  injuries  in  different  parts  of 
the  brain.  If  the  auditory  cells  are  destroyed  in  any  way, 
the  patient  cannot  repeat  the  words  heard.  The  effect  is 
the  same  as  if  the  patient  were  totally  deaf.  Again,  if 
there  is  an  injury  to  the  association  region  in  the  Island  of 
Reil,  the  ability  to  repeat  words  heard  is  impaired.  Fi- 
nally, if  the  motor  centre  for  speech  is  injured,  speaking  of 
any  kind  will  be  impossible.  The  condition  is  known 
as  aphasia,  —  sensory  aphasia  is  due  to  disturbance  of 
the  auditory  region,  motor  aphasia  to  disturbance  of 
the  motor  region.  The  existence  of  sensory  aphasia  is 
of  particular  importance  as  an  evidence  that  the  action 


THE    NERVOUS    SYSTEM  41 

of  the  cortex  is  dependent,  like  the  action  of  the  lower 
centres,  upon  the  excitations  of  sense,  that  all  action  is 
sensori-motor  action.  There  is  no  action  unless  an  im- 
pulse is  received  from  some  sensory  region.  In  each  of 
the  regions  we  have  mentioned,  a  number  of  neurones 
act  together.  Where  we  have  spoken  of  a  single  cell, 
we  might  have  said  group  of  cells,  but  the  course  from 
neurone  to  neurone  is  as  we  have  sketched  it. 

The  relation  of  vision  to  speech,  and  of  vision  and 
audition  to  writing,  follow  the  same  general  rules.  When 
one  reads  aloud,  the  impulse  is  transferred  from  the  visual 
area  to  the  motor  speech  region  through  an  association 
centre.  Injury  to  the  visual  area  or  to  the  sight-speech 
association  region  may  interfere  with  the  process.  The 
resulting  disease  is  known  as  alexia.  Agraphia  (loss  of  the 
capacity  for  writing)  may  be  induced  by  an  injury  to  the 
motor  centres  for  the  control  of  the  arm.  Writing  on 
dictation  ordinarily  disappears  with  speech  in  the  sensory 
forms  of  aphasia.  Each  of  these  paths  has  been  devel- 
oped through  long  practice  and  is  relatively  firmly  es- 
tablished. Any  other  simple  response  to  stimulation 
would  take  a  corresponding  course  and  would  involve 
sensory,  associatory,  and  motor  regions.  Where  the 
paths  are  less  well  established  and  the  response  is  less 
completely  prepared,  the  association  regions  probably 
play  a  larger  part.  There  are  more  possible  connections 
and  more  open  association  paths,  or  at  least  the  open 
paths  in  the  association  regions  are  more  nearly  on  a  par. 
In  consequence  there  is  smaller  chance  of  prophesying 
in  advance  what  course  the  response  will  take.  The  ne- 
cessity for  the  cooperation  of  sensory,  associatory,  and 
motor  neurones  is  none  the  less  certain. 


42  ESSENTIALS   OF   PSYCHOLOGY 

In  addition  to  the  connections  that  are  made  between 
sensory  and  motor  regions  there  are  a  number  of  cases 
in  which  two  sensory  regions  must  be  connected.  Thus 
when  one  touches  a  pencil  in  the  dark,  the  picture  of  the 
object  will  present  itself  before  the  movement  is  made, 
or  simultaneously  with  the  movement.  In  this  case  the 
tactual  cell  excites  a  visual  neurone  or  group  of  neurones. 
In  the  perception  processes  such  associatory  transfers 
are  the  rule  rather  than  the  exception,  as  will  be  seen  in 
a  later  chapter.  Ordinarily  the  association  leads  finally 
to  action  of  some  sort,  but  so  far  as  important  action  is 
concerned,  that  may  be  very  long  delayed.  This  fact  of 
arousing  other  sensory  processes  raises  the  question  as 
to  the  cortical  seat  of  memory  processes  and  imaginings. 
The  most  generally  accepted  answer  at  present  is  that  the 
memories  have  the  same  cortical  regions,  in  fact  the  same 
cortical  cells,  as  the  sensations,  and  that  in  remembering 
the  same  cells  are  excited  as  in  seeing  or  hearing.  Vis- 
ual memories  are  in  the  visual  region,  auditory  memories 
are  in  the  auditory  region,  and  so  on.  The  process  of 
arousing  memories  is  one  of  retracing  old  paths,  very  much 
as  habit  depends  upon  the  renewed  action  of  a  group  of 
motor  neurones  on  the  excitation  of  some  familiar  object. 
The  details  of  the  process  must  occupy  us  in  the  later 
chapters. 

Nerve  Elements  do  not  Act  in  Isolation.  —  One  word 
needs  to  be  added  in  this  connection,  and  that  is  that  the 
single  parts  of  the  nervous  system  probably  do  not  act 
alone.  When  we  speak  of  the  action  of  a  single  group  of 
cells  it  is  probable  that  the  group  is  merely  the  centre 
of  excitation  in  a  very  wide  region.  The  excitation 


THE   NERVOUS    SYSTEM  43 

that  arouses  that  group  spreads  to  very  remote  parts 
of  the  brain.  Action  is  always  of  large  masses  of 
nerve-cells,  but  of  the  mass  certain  parts  are  emphasised, 
the  other  portions  acting  in  very  much  slighter  degree. 
There  is  a  complicated  interplay  of  part  and  part  through- 
out a  very  large  portion  of  the  mass  of  neurones,  although 
only  relatively  few  are  in  great  activity.  The  interac- 
tions that  themselves  do  not  directly  affect  action  serve 
to  guide  the  course  of  the  other  responses.  Each  con- 
tributes its  share  to  the  total  action,  although  one  alone 
stands  out  prominently. 

The  action  of  the  nervous  system,  then,  is  always  de- 
pendent upon  a  transfer  of  some  sort  of  energy  from 
neurone  to  neurone.  The  original  excitation  is  received 
from  the  external  world  and  has  its  final  outcome  in  some 
sort  of  movement.  At  least  two  neurones  are  involved 
in  every  action.  As  the  act  becomes  more  complicated, 
a  larger  and  larger  number  of  neurones  may  inter- 
vene, and  a  larger  and  larger  number  of  stimuli  may 
contribute  to  the  excitation  and  control  of  the  movement. 
At  the  lowest  level  the  stimulus  is  ordinarily  single  or  at 
least  of  one  sort,  and  the  paths  of  motor  discharge  are 
relatively  few.  At  the  second  level  the  neurones  in- 
volved are  still  relatively  few,  but  the  stimuli  are  nu- 
merous and  varied  and  the  paths  of  discharge  are  more 
numerous.  On  the  highest  level  in  the  cortex  all  of  the 
sensory  and  motor  paths  are  concerned,  and  in  addition 
the  effects  of  the  stimuli  that  were  earlier  received  and 
are  stored  in  the  nervous  system  contribute  their  share 
to  the  control  of  action. 

The  different  levels  ordinarily  interact  in  any  response. 


44  ESSENTIALS    OF   PSYCHOLOGY 

Thus,  when  the  hand  is  burned  or  pricked  it  will  usually 
be  drawn  back  reflexly.  This  means,  nervously,  that  the 
sensory  impulse  is  transmitted  to  a  spinal  ganglion  and 
thence  to  the  anterior  grey  cells  of  the  cord,  and  so  down 
to  the  muscle.  But  suppose  that  the  man  is  working  in  a 
bit  of  machinery  with  the  hand  in  front  of  a  knife,  and  the 
finger  is  burned.  The  reflex,  if  it  is  not  too  strong  or 
the  stimulus  is  expected,  will  be  checked  by  the  knowledge 
of  the  danger  from  the  knife.  This  means  that  the  visual 
impression  of  the  knife  has  been  carried  to  the  visual 
area  in  the  cortex  by  way  of  the  eye  and  midbrain  centres. 
The  effect  of  the  arousal  of  the  visual  area  will  be  trans- 
ferred to  the  motor  region,  and  will  serve  to  inhibit  the 
activity  of  the  motor  cells  in  the  cord  that  would  other- 
wise be  involved  in  the  reflex,  or  will  contract  the  muscles 
that  oppose  the  reflex.  In  this  way  the  impressions  from 
the  eye  or  the  memories  derived  from  the  eye  oppose  and 
may  overcome  the  effects  of  the  excitation  from  the  skin. 
The  movement  is  controlled,  not  by  the  tactual  sensations 
alone,  but  by  tactual  sensations  together  with  any  visual 
sensations  and  memories  that  bear  upon  the  situation. 
At  each  level  in  the  nervous  system  as  we  go  upward 
from  the  cord,  there  are  more  neurones  involved.  The 
action  is  in  the  light  of  a  constantly  increasing  number  of 
sensations,  and  many  more  forms  of  response  are  possible. 
But  the  difference  is  one  of  complexity  alone.  The 
beginning  and  the  end  of  the  process  may  be  identical. 
The  impulse  is  propagated  in  the  same  way  and  the 
laws  that  govern  the  selection  of  the  path  are  the  same. 
Our  first  picture  of  the  simple  reflex  explains  the  funda- 
mentals of  the  most  complicated  voluntary  act.  It  is 


THE   NERVOUS    SYSTEM  45 

only  necessary  to  add  new  stimuli  and  new  possibilities 
of  response,  —  to  recognise  that  many  currents  of  nervous 
activity  are  adding  their  quota  to  the  control  of  action. 

EXERCISES 

1.  Draw  neurones  of  three  different  types.     Designate  axones, 
dendrites,  and  end-brushes  in  each  case. 

2.  What  are  afferent  nerves,  efferent  nerves,  ganglia,  white  and 
grey  matter  in  terms  of  neurones  ? 

3.  Describe  the  function  of  the  nervous  system  in  the  simplest  and 
most  general  terms. 

4.  Trace  on  a  diagram  the  course  of  the  reflexes  that  might  be 
excited  by  burning  your  finger.     What  determines  which  one- will 
be  excited  in  any  particular  case  ? 

5.  Draw  the  cerebrum  in  lateral  and  mesial  view  and  indicate 
the  sensory,  motor,  and  association  areas. 

6.  Trace  on  the  diagram  the  path  followed  by  a  nerve  impulse 
when  you  copy  a  sentence. 

7.  Outline  the  action  of  sensory,  association,  and  motor  areas 
when  you  describe  a  landscape  from  memory. 

8.  What  nervous  structures  are  involved  as  one  absent-mindedly 
turns  the  wrong  corner  while  thinking  intently  of  work  ? 

9.  If  possible  dissect  a  sheep's  brain  and  compare  the  structures 
with  the  diagrams. 

REFERENCES 

HOWELL:  Physiology,  pp.  111-252. 
DONALDSON:  The  Growth  of 'the  Brain. 

The  Nervous  System.    American  Text-Book  of  Physiology, 

vol.  ii,  pp.  171-297. 

McDouGALL :  Primer  of  Physiological  Psychology. 
QUAIN:  Anatomy,  vol.  iii. 


CHAPTER  III 

NEURAL  ACTION  IN   RELATION  TO   CONSCIOUSNESS 
AND   BEHAVIOUR 

AFTER  a  discussion  of  the  structure  and  action  of  the 
nervous  system  the  question  of  the  relation  between  these 
physical  processes  and  the  mental  processes  or  behaviour 
naturally  arises.  Popularly  there  is  a  tendency  to  con- 
fuse mind  with  brain.  A  man  is  said  to  have  brains 
when  it  is  meant  merely  that  he  is  effective  or  unusually 
intelligent.  This  is  altogether  without  warrant.  On 
the  contrary,  there  is  little  if  any  similarity  between  ner- 
vous activity  and  the  mental  state.  If  one  could  bring 
the  processes  that  go  on  in  the  brain  when  one  looked  at 
a  landscape  side  by  side  with  the  landscape  and  compare 
them  with  the  landscape  itself,  the  two  would  not  be 
recognised  as  having  any  relation  to  one  another.  Where 
the  landscape  shows  various  forms  and  masses  of  colour, 
the  nervous  activity  consists  in  chemical  reactions  run- 
ning here  and  there  in  the  visual  area  at  the  back  of  the 
brain  and  in  the  nerves  leading  to  and  away  from  it.  We 
have  every  reason  to  believe  that  the  chemical  changes 
stand  in  some  essential  relation  to  the  mental  processes, 
but  it  is  obviously  impossible  to  assert  that  the  two  are 
identical  or  even  that  they  are  similar  in  character.  One 
of  the  problems  that  has  been  most  discussed  in  psy- 
chology and  in  philosophy  is  of  the  exact  relation  that 
may  be  supposed  to  hold  between  the  constantly  shifting 
46 


RELATION   TO    CONSCIOUSNESS   AND   BEHAVIOUR      47 

chemical  changes  in  the  nervous  system  and  the  course 
of  thought.  While  the  answer  makes  little  practical 
difference  in  the  treatment  of  psychological  problems,  it 
is  well  before  going  farther  to  have  a  statement  of  oppos- 
ing theories  and  a  provisional  working  hypothesis. 

Relation  of  Mind  and  Body.  —  A  large  part  of  the 
difficulty  in  understanding  the  relation  of  body  and  mind 
grows  out  of  the  different  ways  in  which  one  must  ap- 
proach the  explanation  of  behaviour.  The  observer  sees 
only  the  stimulus  or  occasion  for  the  action,  the  actor 
appreciates  the  mental  states  that  follow  the  stimulus 
and  precede  the  action,  but  neither  can  see  both  sides  at 
once.  Even  if  the  observer  calls  anatomy  and  physiology 
to  his  aid  and  goes  as  far  as  he  can  by  analogy  from  ex- 
periments on  animals  in  the  attempt  to  find  an  explana- 
tion of  behaviour,  he  gets  only  nerves  and  their  connec- 
tions ;  he  can  never  get  a  view  of  the  consciousness  of  the 
actor.  The  actor  from  his  side  can  never  get  more  than 
consciousness;  he  does  not  become  aware  directly  of 
nerve  or  nervous  activity,  no  matter  how  he  may  seek 
to  penetrate  beneath  his  immediate  consciousness.  The 
outside  observer  sees  excitations  vanish  into  the  nervous 
system  and  sees  actions  result ;  the  actor  sees  the  occasion 
for  his  act  approach,  is  conscious  of  the  resulting  sensation, 
and  knows  that  he  has  acted,  but  knows  nothing  of  the 
nervous  system  that  intervenes.  So  far  no  one  has  been 
able  to  get  the  two  aspects  of  behaviour  connected  in  a 
single  system  of  explanations,  either  by  direct  observa- 
tion or  in  theory.  At  present  it  is  universally  accepted 
that  mental  state  and  bodily  or  nervous  activity  are 
always  found  together,  but  care  is  taken  not  to  assert  that 


48  ESSENTIALS   OF   PSYCHOLOGY 

one  is  the  cause  of  the  other.  The  implication  is  that  they 
are  related  in  some  essential  and  fundamental  way,  but 
what  that  connection  is,  is  not  stated.  It  is  customary 
to  explain  any  mental  process  in  terms  of  other  mental 
processes,  and  to  explain  all  nervous  action  by  other 
nervous  activities,  but  no  attempt  is  made  to  explain  one 
in  terms  of  the  other,  further  than  to  say  that  the  two 
series  are  always  found  together  and  run  on  side  by  side. 
For  our  purposes  it  is  not  necessary  to  discuss  the  theories 
that  have  been  developed  to  explain  the  connection. 
We  may  leave  the  whole  problem  open,  as  the  facts  of 
psychology  are  the  same  whatever  theory  may  ultimately 
prevail.  For  convenience  we  shall  often  seem  to  imply 
that  activity  in  sensory  neurones  produces  changes  in 
consciousness  and  that  ideas  start  motor  discharges  that 
lead  to  action.  This  is  not  to  be  regarded  as  committing 
the  author  to  any  theory  of  the  real  connection  between 
body  and  mind,  but  as  a  lapse  into  popular  speech. 

The  Synapse  and  the  Formation  of  Habits. — 
While  it  is  assured  that  consciousness  is  dependent 
upon  the  activity  of  the  nervous  system,  and  that  certain 
conscious  processes  are  connected  with  the  activity  of 
certain  nervous  structures,  it  is  also  important  to  know 
what  change  there  is  in  the  elements  of  the  nervous  system 
as  a  result  of  action.  Upon  their  changed  character  as  a 
result  of  earlier  action  depends  most  of  the  possibility  of 
education  and  of  improvement  in  behaviour.  Formation 
of  habits  and  the  acquirement  of  memories  are  the  most 
striking  of  the  mental  and  physical  capacities  that  are 
directly  referred  to  the  nervous  system.  At  present  the 
tendency  is  to  explain  all  learning  as  due  to  a  change  at 


RELATION   TO   CONSCIOUSNESS   AND   BEHAVIOUR      49 

the  point  where  two  neurones  come  together,  where  the 
end-brush  of  one  comes  into  contact  with  the  dendrites  of 


FIG.  8.  —  Shows  the  complexity  of  interconnections  (number  of  synapses)  be- 
tween neurones  in  the  cortex.  (From  Barker,  Fig.  655,  after  Ramon  y  Cajal.) 

another.  This  point,  as  was  said,  has  been  called  the 
synapse.  As  was  seen  in  the  preceding  chapter,  the  syn- 
apse governs  the  course  of  the  impulse.  Each  sensory 
path  makes  connections  with  several  motor  and  associat- 
ing paths  or  neurones  and  any  impulse  will  take  the  path 


50  ESSENTIALS   OF   PSYCHOLOGY 

that  offers  least  resistance.  The  point  of  departure  for  the 
various  alternative  paths  is  a  synapse,  and  the  ease  with 
which  the  synapses  open  determines  the  resistance  of  the 
paths.  The  ease  with  which  the  synapses  open  is  deter- 
mined first  by  inheritance,  second  by  use.  The  reflexes 
of  the  cord  run  their  course  through  synapses  that  are 
prepared  at  birth.  The  course  of  an  impulse  through 
the  cortex  is  largely  controlled  by  synapses  that  owe 
their  degree  of  resistance  to  the  frequency  with  which 
they  have  been  used.  Evidently,  then,  the  most  impor- 
tant question  of  nervous  physiology  for  the  psychologist 
is  what  is  the  nature  of  the  synapse  and  of  its  action? 

The  details  of  the  mechanism  of  the  synapse  are  still 
altogether  lacking,  although  numerous  theories  have  been 
developed  to  explain  it.  All  agree  that  whenever  two 
neurones  are  active  at  the  same  time  some  change  is  in- 
duced in  the  synapse  that  makes  it  act  more  readily  later. 
The  two  neurones  become  more  nearly  a  single  unit  for 
action.  Two  suggestions  as  to  what  the  change  is  may 
be  mentioned  as  typical.  The  older,  and  in  many  ways 
the  simpler,  regards  the  neurones  as  living  organisms  that 
still  possess  at  their  extremities  the  power  of  motion  in- 
herent in  the  amceba-like  prototype.  When  both  cells 
are  active  the  processes  extend  and  come  into  contact, 
and  the  chemical  action  that  is  the  basis  of  the  activity 
of  the  one  in  some  way  excites  a  similar  activity  in  the 
other.  The  action  of  the  processes,  particularly  of  the 
dendrite,  leaves  behind  it  a  disposition  to  act  again  more 
easily  in  the  same  way.  As  a  result  of  this  disposition, 
the  same  extension  is  repeated  on  suitable  occasion  and 
the  connection  between  the  cells  and  their  simultaneous 


RELATION   TO    CONSCIOUSNESS   AND   BEHAVIOUR      51 

action  is  renewed.  What  the  nature  of  the  change  may 
be  is  not  made  very  clear.  It  may  be  an  actual  physical 
bond  that  persists  when  the  end-brush  of  one  neurone  has 
once  been  brought  into  contact  with  the  dendrite  of  an- 
other, or  it  may  be  that  one  or  the  other  of  the  processes 
takes  on  a  habit  of  extending  in  the  way  that  brought  it 
into  contact  with  the  other.  The  original  obstruction 
to  the  transfer  of  the  action  from  one  neurone  to  another 
is  spatial,  and  the  original  gap  is  bridged  by  the  move- 
ment of  processes,  a  movement  that  when  once  made 
leaves  a  permanent  tendency  to  the  union  of  the  neurones. 
The  more  recent  theory,  favoured  by  Sherrington,  the 
English  physiologist,  is  that  the  synapse  opposes  the  pas- 
sage of  an  excitation  in  much  the  same  way  that  a  mem- 
brane opposes  the  transfer  of  fluids.  At  first  this  resist- 
ance is  very  great,  but  it  is  lessened  with  each  act.  On 
this  theory  the  change  in  the  synapse  is  chemical  in 
character.  Here  again  the  exact  nature  of  the  change 
is  not  asserted.  On  either  theory  the  synapse  is  the 
point  where  action  leaves  its  impress  upon  the  nervous 
system,  and  it  is  here  that  learning  has  its  effect.  The 
change  that  comes  with  action  is  a  lessened  resistance  at 
the  synapse,  whether  it  be  due  to  the  coming  closer  of  the 
processes  or  to  a  chemical  change  that  makes  more  per- 
meable the  relatively  impermeable  membrane  that  at 
first  separates  the  neurones.  On  either  theory  it  is  pos- 
sible to  picture  the  synapse  as  a  valve  that  controls  the 
interaction  of  nerve  elements,  —  that  governs  the  passage 
of  the  nervous  impulse  from  unit  to  unit.  At  first  the 
valves  are  stiff  and  open  only  to  strong  currents ;  with 
use  they  work  more  easily  until  those  most  difficult  at 


52  ESSENTIALS   OF    PSYCHOLOGY 

birth  may  become  as  delicate  in  action  as  those  that  were 
at  birth  most  permeable.  As  the  outcome  of  our  discus- 
sion, we  have  a  picture  of  the  nervous  system  as  a  mass 
of  relatively  independent  amceba-like  cells  that  are  held 
in  a  definite  position  and  relation  to  one  another  by  a 
cage  of  bone.  At  the  beginning  certain  of  the  neurones 
constitute  a  path  for  an  impulse  from  sense-organs  to 
muscles.  These  original  paths  are  few  and  make  possible 
only  the  most  essential  activities  for  the  continuance  of 
the  life  of  the  individual.  Additional  paths  of  connection 
are  formed  by  each  activity,  physical  and  mental.  When- 
ever any  two  neurones  chance  to  act  together  a  connection 
is  formed  between  them,  the  original  gap  is  bridged,  and 
they  come  to  form  part  of  a  new  pathway  from  sense- 
organ  to  muscle.  Sometimes  the  most  important  of  the 
neurones  that  are  connected  lie  within  the  cortex,  and  the 
learning  that  results  is  primarily  learning  of  ideas  rather 
than  of  movements,  but  the  principle  is  the  same  as  be- 
fore. Learning,  whether  of  new  movements  or  of  new 
ideas,  is  a  process  of  making  easier  the  passage  of  an  im- 
pulse from  neurone  to  neurone  and  is  fundamentally  the 
same  everywhere. 

When  the  connections  hi  the  nervous  system  have  once 
been  formed,  the  course  of  a  nervous  impulse  is  deter- 
mined by  the  intensity  of  the  stimulus  and  the  openness 
of  the  synapses.  The  course  of  a  reflex  through  the  ner- 
vous system  depends  upon  the  innate  connections  of  the 
synapses.  In  the  cord,  for  example,  a  slight  stimulus  on 
the  hand  arouses  the  muscles  of  that  arm; -a  stronger  one 
excites  the  corresponding  member  of  the  opposite  side ; 
still  stronger  impressions  cause  contractions  in  the  legs, 


RELATION    TO    CONSCIOUSNESS   AND    BEHAVIOUR      53 

and  finally  contractions  will  spread  to  all  of  the  muscles 
of  the  trunk.  Translated  into  terms  of  neurones  and 
synapses,  this  indicates  that  the  synapse  that  opens  most 
readily  is  the  one  between  the  sensory  neurone  and  the 
motor  neurone  at  the  same  level  and  on  the  same  side  of 
the  cord.  Slight  stimuli  are  strong  enough  to  force  their 
way  across  this  gap.  As  the  stimulus  becomes  stronger, 
the  synapses  that  are  found  in  the  opposite  side  of  the 
cord  open,  then  those  that  lie  at  the  higher  and  lower 
levels.  The  course  of  the  impulse  and  the  selection  of  the 
movement  depend  altogether  upon  the  ease  with  which 
synapses  open  and  the  strength  of  the  stimulus.  The 
same  factors  determine  the  selection  in  the  more  com- 
plicated reactions  of  the  higher  brain  centres.  In  man 
the  sort  of  action  that  will  be  called  out  by  a  situation 
depends  upon  the  habits  he  has  formed,  and  these  in  turn 
are  due  to  connections  between  neurones  in  different 
parts  of  the  brain.  In  a  soldier  trained  to  answer  to  the 
word  of  command  the  readiest  response  is  to  obey,  how- 
ever that  action  may  conflict  with  his  instincts.  The 
synapses  have  opened  so  frequently  between  the  centres 
for  hearing  and  the  movements  that  are  called  out  by  the 
order  that  the  stimulus  suffices  to  open  them,  however  un- 
favourable the  other  circumstances.  In  these  responses, 
too,  stronger  stimuli  arouse  more  diffuse  responses. 
Where  a  single  command  when  in  ranks  calls  out  im- 
mediate response,  the  sudden  charge  of  an  enemy  when 
the  ranks  are  broken  and  the  men  are  in  disorder  may 
cause  sudden  diffuse  responses  that  will  overcome  the 
effects  of  the  habitual  response.  Similarly,  in  a  game  of 
baseball  the  habitual  response  will  be  made  immediately 


54  ESSENTIALS    OF   PSYCHOLOGY 

and  accurately  when  the  stimulus  is  slight  and  the  cir- 
cumstances normal,  but  when  some  strong  stimulus  or 
some  emotionally  disturbing  event  takes  place  at  the 
moment,  the  suitable  habitual  response  is  ordinarily  lost 
in  the  general  overflow  to  neighbouring  muscles.  The  ball 
is  often  thrown  over  the  first  baseman's  head  at  a  critical 
moment.  While  in  the  higher  habitual  responses  more 
complicated  factors  must  be  taken  into  consideration, 
the  character  of  the  response  still  depends  upon  the  open- 
ness of  the  synapses  at  the  moment  and  the  intensity  of 
the  stimulus  or  its  appeal  for  the  individual.  In  essen- 
tials, the  response  of  the  higher  neurones  and  paths  of 
connection  follow  the  same  laws  as  the  lower. 

The  Formation  of  Habits.  —  One  of  the  most  impor- 
tant facts  that  can  be  referred  to  the  action  of  the  nervous 
system  directly  is  the  formation  of  habits.  This,  as  has 
been  said,  is  due  primarily  to  the  opening  of  synapses  by 
use.  Habit,  whether  for  good  or  ill,  is  one  of  the  most 
striking  elements  in  any  explanation  of  behaviour.  As 
it  is  fundamental  for  many  of  the  psychological  explana- 
tions, we  may  begin  our  discussion  with  a  brief  sum- 
mary of  its  laws  and  applications.  In  popular  speech 
habit,  for  some  reason,  implies  bad  habit,  but  this  re- 
striction of  the  term  is  altogether  unjustifiable.  Absence 
of  habit  would  mean  complete  loss  of  efficiency.  Most  of 
eating,  walking,  talking,  and  all  of  the  frequent  and  im- 
portant actions  of  everyday  life  are  habits  in  whole  or  in 
part.  Dressing  is  a  habit.  You  do  not  think  as  you  put 
on  your  garments.  Your  hands  find  their  way  to  the 
buttons  without  thought  and  without  your  being  con- 
scious that  they  are  moving.  The  tie  is  adjusted  with  no 


RELATION    TO    CONSCIOUSNESS    AND    BEHAVIOUR      55 

knowledge  of  the  separate  movements.  Were  you  asked 
to  describe  the  movements  made  in  tying  a  cravat,  you 
probably  could  not  do  so,  although  the  operation  is  run 
through  daily  without  mistake.  If  we  turn  from  a  dis- 
cussion of  the  omnipresence  of  habit  to  the  question  of 
what  goes  on  in  the  nervous  system  when  a  habit  is  ac- 
quired, we  get  back  to  our  problem  of  the  synapse  and 
its  relations.  Each  time  an  act  is  performed,  it  matters 
not  how,  there  is  some  change  in  the  synapses  between 
neurones.  The  effect  of  the  act  persists  and  becomes 
stronger  with  each  repetition.  After  several  repetitions 
the  connection  between  the  cells  becomes  so  close  that 
whenever  the  particular  sensory  cell  is  excited,  the  im- 
pulse spreads  to  the  motor  cells  that  were  active  before, 
and  the  neurones  grow  more  and  more  to  constitute  what 
is  practically  a  single  structure.  The  formation  of  habits 
is  thus  a  process  of  decreasing  the  resistance  of  the  syn- 
apses in  the  different  possible  paths  of  transmission.  Ul- 
timately it  is  due  to  a  change  of  some  kind  in  the  synapses. 
When  a  sensory  neurone  is  excited,  one  of  the  synapses  is 
more  open  than  the  others.  This  is  traversed  by  the 
impulse  and  the  corresponding  muscle  responds.  The 
opening  of  the  synapse  has  in  every  case  been  brought 
about  by  the  simultaneous  action  of  the  two  neurones. 

The  Omnipresence  of  Habit.  —  The  process  of  form- 
ing a  habit  is  relatively  simple,  but  the  effect  of  habit  for- 
mation has  the  most  far-reaching  importance.  Every 
act  of  any  kind  is  the  forerunner  of  other  acts  of  the  same 
kind.  At  first  the  habit  is  easily  changed ;  but  if  fre- 
quently persisted  in,  the  time  comes  when  that  movement 
must  be  made  whenever  the  particular  occasion  presents 


56  ESSENTIALS    OF   PSYCHOLOGY 

itself,  without  reference  to  the  other  circumstances  of  the 
moment.  Obviously  when  the  movements  are  repeated 
to  this  degree  of  fixedness,  it  is  essential  that  the  move- 
ments chosen  for  fixation  shall  be  helpful  or  harmless. 
The  useful  man  is  for  the  greater  part  marked  off  from  the 
useless  and  the  vicious  by  the  nature  of  his  habits.  In- 
dustry or  indolence,  good  temper  or  bad  temper,  even 
virtue  or  vice,  are  in  the  last  analysis  largely  matters  of 
habit.  One  forms  the  habit  of  working  at  certain  times 
of  the  day,  and  soon  if  one  is  not  busy  at  that  time  one 
experiences  a  lively  sense  of  discomfort.  Or,  on  the  con- 
trary, one  forms  the  habit  of  loafing  all  day.  Work  then 
becomes  distasteful  and  indolent  irresponsibility  is  es- 
tablished. Losing  one's  temper  is  largely  a  habit,  as  is 
self-control.  Each  time  one  is  provoked  by  a  trifle,  it 
becomes  the  more  difficult  to  look  calmly  at  an  unpleasant 
episode ;  while  each  time  one  remains  calm  under  difficult 
circumstances,  strength  is  gained  for  later  difficulties. 
Similarly,  whenever  temptation  is  resisted,  virtue  gains  a 
victory ;  when  temptation  is  yielded  to,  new  weaknesses 
develop.  Frequent  yielding  makes  resistance  practically 
impossible.  A  bank  president  of  established  morals  could 
no  more  step  out  and  pick  a  pocket  that  was  temptingly 
unprotected  than  he  could  fly.  The  habitual  drunkard 
can  no  more  resist  the  invitation  to  have  a  glass  than  he 
can  resist  the  action  of  gravitation  while  falling  freely 
through  space.  Frequent  giving  in  has  entirely  de- 
stroyed his  original  freedom  of  choice. 

We  are  all  constantly  forging  chains  of  action  in  our 
nervous  system  that  we  shall  never  be  able  to  break. 
Fortunate  is  the  man  whose  chains  are  all  suited  to  the 


RELATION   TO    CONSCIOUSNESS   AND   BEHAVIOUR      57 

life  he  is  compelled  to  live.  He  was  once  free  in  the  sense 
of  our  present  problem,  but  after  a  few  experiences  he 
becomes  bound  to  his  past  by  chains  that  not  even  the 
strongest  impulses  can  break.  Habits  are  not  restricted 
to  action,  but  show  themselves  even  in  the  features. 
Much  has  been  said  from  time  to  time  in  the  history  of 
science  of  the  ability  to  determine  character  from  the 
face.  Each  movement  of  the  muscles  of  the  face  has 
left  its  impress  upon  the  muscles  and  the  skin,  just  as 
each  action  has  left  its  impress  upon  the  nerve-cells. 
One  can  tell  at  a  glance  at  the  face,  even  in  repose,  what 
its  most  characteristic  responses  have  been  and  can  form 
some  idea  of  the  character  of  the  man,  of  the  effects  that 
have  been  left  by  the  same  actions  upon  the  nerve-cells 
which  show  themselves  when  the  man  is  called  upon 
to  act.  A  weak  man,  a  strong  man,  even  more  truly 
a  jovial  man  or  a  crabbed  man,  carries  the  marks  upon 
his  face.  These  marks  are  but  evidence  of  the  changes 
that  the  same  set  of  acts  has  left  upon  the  synapses  of  the 
nervous  system  everywhere  along  the  paths  of  action. 

Habits  Essential  to  Action.  —  Habit  not  only  limits 
choice  but  through  early  training  makes  choice  possible. 
The  adult  ordinarily  chooses  one  habit  rather  than  an- 
other; he  does  not  choose  between  some  action  that  is 
habitual  and  something  that  has  never  been  done  before. 
What  has  never  been  done  is  ordinarily  not  within  the 
power  of  the  individual.  For  example,  you  cannot  speak 
the  Russian  word  for  prince  and  could  not  if  some  one 
should  first  pronounce  the  word  for  you.  You  cannot 
because  you  have  never  developed  the  habit.  When  you 
do  choose  to  speak  an  English  word,  you  do  it  because 


58  ESSENTIALS   OF   PSYCHOLOGY 

you  have  that  habit  fully  developed.  Had  you  never 
formed  habits  of  .speaking  you  would  be  as  power- 
less in  English  as  in  Russian.  As  all  of  our  intellectual 
operations  are  expressed  in  language,  habit  is  in  the 
highest  sense  a  powerful,  an  indispensable  tool  of  think- 
ing. But  that  is  not  all.  If  you  eliminate  from  the 
various  intellectual  activities  all  that  belongs  to  habit, 
most  of  the  higher  mental  operations  become  impossible. 
Habit,  like  fire,  is  a  cruel  master  but  an  invaluable 
servant.  Without  it  all  action  at  once  ceases  or  at  the 
best  becomes  but  a  painful  process  of  feeling  one's  way 
through  even  the  simplest  act. 

Association  of  Ideas  a  Form  of  Habit.  —  The  processes 
of  association  of  ideas,  which  are  fundamental  for  think- 
ing, are  in  their  nature  similar  to  habit.  The  recall  of 
any  memory  necessitates  the  stimulus  of  some  earlier 
connected  event.  Old  experiences  return  only  in  con- 
nection with  some  earlier  events  now  in  consciousness. 
On  the  nervous  side  this  means  that  the  cells  in  the  cortex 
corresponding  to  the  two  ideas  have  been  active  together 
and  that  the  resistance  of  the  common  synapse  has  been 
reduced  by  the  simultaneous  action  of  the  two  neurones. 
When  one  presents  itself,,  the  impulse  spreads  through 
the  synapse  of  least  resistance  to  the  related  cell  and  the 
old  idea  is  recalled.  All  recall  is  dependent  upon  the 
connection  of  ideas,  and  ideas  are  connected  only  as 
the  neurones  are  united  through  the  reduced  resistance  of 
the  synapses.  The  association  processes  are  thus  in  every 
particular  similar  to  habits.  They  might  be  called 
habits  of  neurones  in  the  cortex.  The  only  difference 
worth  emphasising  is  that  in  this  case  there  is  no 
movement  of  muscles  accompanying  the  activity  of  the 


RELATION   TO    CONSCIOUSNESS   AND   BEHAVIOUR      59 

cortical  cells.  Even  this  difference  is  not  always  present, 
for  the  cortical  cells  whenever  active  tend  to  call  out 
movements,  often  very  slight,  sometimes  nothing  more 
than  the  tendency  to  movement.  If  we  include  associa- 
tion among  the  habits,  we  may  say  with  complete  as- 
surance that  no  intellectual  activity  of  any  kind  goes  on 
except  on  the  basis  of  habit.  Habit  and  association  are 
the  two  fundamental  facts  upon  which  all  of  our  activity, 
mental  or  physical,  depends.  That  either  should  be 
lacking  is  inconceivable.  Were  they  lacking,  man, 
either  as  a  mental  or  as  a  physical  being,  would  not  be 
what  he  is.  The  detailed  discussion  of  the  use  of  habits 
must  be  left  to  later  chapters. 

EXERCISES 

1.  Describe  the  nervous  and  mental  operations  involved  in  read- 
ing aloud.    How  are  they  different  ? 

2.  What  connection  may  be  asserted  to  exist  between  the  two 
series  of  events  described  above  ?    Is  either  the  cause  of  the  other  ? 

3.  'What  change  takes  place  in  the  nervous  system  when  any 
movement  is  made  ? 

4.  How  does  this  change  affect  later  action  ? 

5.  Trace  as  closely  as  you  can  the  different  steps  in  the  formation 
of  some  simple  habit,  such,  for  example,  as  learning  to  tie  a  new  sort 
of  cravat  or  learning  to  use  some  new  tool. 

6.  Find  instances  of  the  dependence  of  character  upon  habit. 

7.  What  are  some  of  your  intellectual  habits  ? 

REFERENCES 

TITCHENER  :  Text-Book  of  Psychology,  sec.  4. 

JUDD  :  Psychology,  pp.  61-64. 

PILLSBURY:  Attention,  pp.  129-225. 

McDouGALL:   Primer  of  Physiological  Psychology,  pp.  14-107. 

JAMES  :  Principles  of  Psychology,  vol.  i,  ch.  iv. 

ANGELL  :  Psychology,  ch.  iii. 


CHAPTER  IV 
SENSATION 

THE  generally  accepted  first  problem  in  psychology  is 
to  determine  the  character  of  consciousness  as  we  im- 
mediately experience  it.  At  this  moment  the  conscious- 
ness of  the  reader  is  made  up  of  a  number  of  processes. 
Experiences  are  received  through  the  eyes  that  constitute 
or  suggest  the  book  with  its  physical  appearance.  At 
the  same  time  you  acquire  certain  elements  of  knowledge 
from  the  words  on  its  page.  Your  mind  wanders  now 
and  again  to  the  thought  of  the  game  you  would  like  to 
be  having  or  of  the  recitation  that  you  would  like  to  make 
on  the  morrow,  or  to  the  entertainment  of  the  evening, 
or  to  some  other  topic.  Accompanying  each  of  these  pro- 
cesses are  feelings  of  pleasure  or  displeasure,  and  in  many 
cases  emotions  of  greater  or  less  intensity.  Obviously 
even  the  simplest  consciousness  is  a  very  complex  affair. 
To  attempt  to  describe  or  to  classify  the  different  sorts  of 
consciousness  taken  in  this  concrete  way  would  evidently 
be  an  endless  task,  and  the  result  would  be  uncertain. 
In  practice  the  undertaking  is  made  easier  by  the  fact 
that  the  memory  processes  and  the  immediate  sensation 
processes  have  approximately  the  same  qualities.  A 
remembered  or  imagined  red  is  of  the  same  quality,  ap- 
proximately, as  the  red  that  is  seen  directly.  Leaving 
60 


SENSATION  6 1 

aside  the  feeling  processes  f9r  the  moment,  we  may  say 
that  the  qualities  of  consciousness  are  the  qualities  of 
sense.  Since  Locke  it  has  been  an  axiom  of  psychology 
that  there  is  nothing  in  mind  that  was  not  previously 
in  sense.  It  is  true  undoubtedly  that  one  cannot  think 
of  a  colour  that  has  never  been  seen.  Try  to  picture  to 
yourself  what  the  ultra-violet  waves  would  be  like  to  an 
eye  that  had  developed  a  capacity  to  see  them,  and  you 
will  find  that  you  can  imagine  no  colour  that  is  not  com- 
pounded out  of  those  that  are  found  in  the  spectrum. 
Any  similar  attempt  to  produce  an  imaginary  quality  that 
has  not  been  received  through  some  sense-organ  will  be 
fruitless.  The  qualities  of  memory  and  imagination  are 
limited  to  those  that  are  received  through  the  senses. 
New  things  may  be  compounded  out  of  these  qualities, 
but  the  number  of  qualities  is  fixed  by  the  elements  that 
may  be  received  through  the  sense-organs.  Evidently, 
then,  the  first  task  that  confronts  us  as  we  undertake  a 
description  of  the  nature  of  consciousness  or  of  its  com- 
ponents is  to  determine  the  number  of  sense  qualities. 
We  approach  this  task  confident  that  its  solution  will 
determine,  not  merely  the  number  of  sensory  qualities, 
but  the  number  of  qualities  that  may  be  remembered  or 
imagined  as  well. 

Doctrine  of  Specific  Energies  of  Sensory  Ends.  — 
The  determination  of  the  number  of  sensory  qualities 
is  not  so  simple  and  easy  as  might  at  first  appear. 
Whether  one  shall  call  each  distinguishable  colour  in  the 
spectrum  a  single  sensation  or  shall  regard  them  all  as 
compounded  of  a  few  simple  qualities,  is  a  question  that 
cannot  be  decided  by  direct  observation.  A  theory  that 


62  ESSENTIALS    OF   PSYCHOLOGY 

was  first  suggested  by  Johannes  Miiller,  the  pioneer  in 
modem  physiology,  offers  perhaps  the  most  convenient 
principle  to  guide  us  in  the  determination  of  the  number 
of  simple  qualities.  Briefly,  this  law  asserts  that  any 
sense-organ  must  always  give  its  own  quality  of  sensa- 
tion, no  matter  how  it  may  be  excited.  Simplest  evi- 
dence of  this  may  be  offered  by  pressing  the  eyeball  with 
the  finger.  You  will  notice  about  the  circle  of  pressure 
a  ring  of  light  of  a  quality  that  might  have  been  induced 
by  a  ray  of  light.  An  electric  current  passed  through 
the  eye  will  also  produce  a  visual  sensation,  as  will  jarring 
the  optical  apparatus  by  falling  ('  seeing  stars  ').  Con- 
versely, it  may  be  said  that  there  can  be  no  more  qualities 
of  sensation  than  there  are  different  kinds  of  sensory 
end  organs.  If  the  quality  of  the  sensation  depends  upon 
the  character  of  the  sense-organ  that  receives  it,  and  not 
upon  the  nature  of  the  stimulus,  the  number  of  sense 
qualities  must  be  as  great  as,  and  no  greater  than,  the 
number  of  sensory  ends.  Since  the  same  stimulus  often 
gives  different  results  upon  several  different  sense-organs, 
the  difference  must  be  due  to  the  organ,  not  to  the  stimulus. 
Many  instances  may  be  enumerated.  A  vibration  of 
ether  may  excite  the  sensation  red  upon  the  retina  of  the 
eye,  a  sensation  of  warmth  upon  the  skin.  The  electric 
•  current  gives  a  different  sense  quality  for  each  sense- 
organ,  —  pain  on  the  skin,  taste  on  the  tongue,  and  so  on. 
If  we  accept  this  law,  it  follows  that  we  can  determine 
the  number  of  different  kinds  of  sensation  if  we  can  dis- 
cover the  number  of  distinct  sensory  end  organs. 

The  Development  of.  Sensations.  —  The  development 
of  the  sense  qualities  depends  upon  and  goes  hand  in  hand 


SENSATION  63 

with  the  development  of  the  sensory  endings.  In  the 
simplest  organisms  there  is  no  differentiation  of  sensory 
organs,  and  consciousness  probably  shows  no  differences 
whatever.  All  stimuli  give  rise  to  exactly  the  same  effect. 
Taste  is  not  different  from  touch,  sight  from  hearing,  — 
if  hearing  be  present  at  all.  All  forms  of  stimuli  excite 
the  same  organ  and  in  consequence  must  give  the  same 
effect.  As  differentiation  takes  place  in  the  animal  series, 
new  organs  are  developed  and  new  sense  qualities  make 
their  appearance.  At  the  level  of  insects  most  of  the 
senses  found  in  man  are  pretty  well  differentiated.  Even 
in  man,  however,  not  all  of  the  physical  stimuli  have  cor- 
responding sensations.  The  electric  and  magnetic  forces 
have  no  sense-organs  and  are  not  recognised  as  separate 
qualities.  For  that  reason,  too,  knowledge  of  electrical 
and  magnetic  phenomena  developed  relatively  late.  In- 
direct evidence  obtained  through  the  other  senses  alone 
gives  knowledge  of  their  existence.  Our  problem  in  this 
chapter  is  to  determine  the  number  of  different  kinds  of 
sensory  ends  that  the  human  organism  presents  to  the  ex- 
ternal world,  confident  that  this  will  also  give  the  number 
of  distinct  conscious  qualities. 

Sensations  of  Temperature.  —  We  may  begin  to  the 
best  advantage  with  the  sensations  derived  from  the  skin. 
The  skin  is  probably  the  simplest  of  the  sense-organs, 
although  it  is  far  more  complex  than  one  is  inclined  to 
believe.  The  ordinary  assumption  seems  to  be  that  the 
skin  is  a  comparatively  homogeneous  surface  with  but 
one  sense  quality.  Recent  investigation,  beginning  in 
the  early  eighties  of  the  last  century,  has  shown  that  the 
skin  has  four  senses  and  that  each  is  distinct  in  quality 


64  ESSENTIALS    OF   PSYCHOLOGY 

and  in  sense-organ.  Two  of  these  respond  primarily  to 
mechanical  stimulation,  two  to  temperature.  The  me- 
chanical senses  are  pressure  and  pain,  the  temperature 
senses  are  warmth  and  cold.  Evidence  for  the  two  tem- 
perature senses  is  most  readily  obtained  by  the  beginner. 
If  one  will  but  run  over  the  skin  with  the  point  of  a  rod 
heated  above  the  body  temperature,  he  will  notice  that 
the  rod  feels  warm  only  here  and  there  at  points  separated 
by  fairly  large  areas.  These  spots  were  found  by  von 
Frey  to  average  about  one  and  one-half  to  the  square 
centimetre.  If  the  rod  be  cooled  below  the  temperature 


FIG.  9.  —  Map  of  warm  and  cold  spots  on  volar  surface  of  forearm.  The  dots 
represent  warm  spots  as  tested  at  a  temperature  of  4i°-48°  C. ;  the  crosses, 
cold  spots  as  tested  at  10°.  (From  Ho  well,  after  von  Frey.) 


SENSATION  65 

of  the  skin,  cold  is  noticed  at  many  more  spots,  about 
thirteen  to  the  square  centimetre,  but  still  wide  areas 
without  temperature  sensations  intervene.  While,  then, 
the  physicist  assures  us  that  cold  is  nothing  but  the 
absence  of  heat  so  far  as  energy  is  concerned,  it  is  un- 
doubted that  physiologically  and  psychologically  cold  is 
just  as  truly  a  distinct  sensation  as  warmth.  Not  only 
is  it  proved  by  mapping  the  spots  that  the  temperature 
senses  are  distinct,  but  the  result  is  confirmed  by  a  num- 
ber of  related  facts,  (i)  Stimulation  of  a  well-marked 
cold  spot  always  gives  cold  only,  no  matter  what  the 
source.  Pressure,  the  electric  current,  even  the  warmth 
obtained  by  concentrating  the  sun's  rays  upon  the  spot 
by  a  small  lens,  all  give  the  same  sensation  of  cold. 
Warm  spots  give  very  much  the  same  result,  except  that 
they  seem  rather  more  difficult  to  excite  than  the  cold 
spots.  (2)  Certain  parts  of  the  body,  the  cornea  of  the 
eye,  e.g.,  lack  warm  spots  altogether,  and  there  are 
relatively  large  areas  where  cold  spots  are  lacking. 
(3)  Certain  chemicals,  e.g.  menthol  for  cold,  carbon  dioxide 
for  warm,  will  excite  one  sort  of  spot,  but  not  the  other. 
All  these  facts  go  to  show  that  cold  and  warmth  are  in- 
dependent senses  with  independent  nerve  ends  in  the 
skin. 

Physiological  Temperature  Scale  — The  response  of 
the  nerve  ends  to  the  different  changes  in  temperature 
is  indicated  in  the  accompanying  diagram.  The  physi- 
ological zero  point  lies  somewhere  in  the  neighbourhood 
of  30°  C.  The  variation  is  from  28°  or  below  to  34°  or 
above,  according  to  the  temperature  to  which  the  body 
has  been  adjusted.  At  any  one  time  the  limit  will  be  but 


66 


ESSENTIALS    OF    PSYCHOLOGY 


a  fraction  of  a  degree.  Below  this  point  all  temperatures 
excite  the  cold  organ;  above,  all  excite  the  organ  of 
warmth.  Very  low  temperatures,  from  12°  downward, 


\ 


40  50 

1 
I       ,        * 


FIG.  10. —  Shows  the  sense  organs  stimulated,  and  approximate  degree  of  stimula- 
tion at  the  different  temperatures.  The  figures  on  the  base  line  indicate  the 
temperature  in  centigrade,  the  height  of  the  line  the  amount  of  stimulation. 
(After  von  Frey :  '  Vorlesungen  iiber  Physiologic,'  Fig.  50.) 

also  excite  the  nerves  of  pain  which  give  the  sensation 
of  burning  or  biting  cold.  Above  the  neutral  point, 
at  about  45°  C.,  warm  becomes  hot.  In  consciousness 
it  is  marked  off  from  warm  by  a  very  sharp  line. 
Physiologically,  the  difference  is  due  to  the  presence  of 
the  sensation  of  cold.  Hot  is  a  compound  of  warm  and 
cold.  This  excitation  of  cold  spots  by  heat  has  been 
called  the  paradoxical  cold  sensation.  Beyond  this,  at 


SENSATION  67 

some  50°  C.,  pain  is  also  aroused  and  gives  burning  heat. 
All  the  temperature  effects  are  produced  by  combina- 
tions of  the  excitations  of  the  three  sense  endings  of 
cold,  warmth,  and  pain. 

Cutaneous  Sensations  from  Mechanical  Stimuli.  — 
There  are  two  sense  qualities  that  may  be  excited  mechan- 
ically, pressure  and  pain.  Somewhat  the  same  differentia- 
tion must  be  made  between  them  as  between  the  tempera- 
ture senses.  If  one  press  gently  upon  the  different  areas 
of  the  skin  with  a  sharply  pointed  wooden  rod  or  a  short 
hair,  pressure  will  be  felt  only  here  and  there.  These 
points  are  known  as  the  pressure  spots.  They  are  found 
closer  together  on  the  average  than  either  class  of  tem- 
perature spots.  They  vary  from  about  nine  to  some  three 
hundred  to  the  centimetre.  These  pressure  spots  are 
relatively  easy  to  excite,  —  they  are  affected  by  hairs 
that  exert  a  pressure  of  a  milligram  or  more.  The  pain 
spots  are  much  more  closely  crowded  and  are  stimulated 
with  greater  difficulty.  They  are  most  easily  found  by 
pressing  upon  the  different  points  on  the  skin  with  a  well- 
sharpened  horsehair.  It  has  been  shown  that  200  or 
more  points  to  the  centimetre  give  rise  to  the  pain  sensa- 
tion. That  pain  is  not  merely  a  more  intense  pressure, 
as  was  thought  for  a  long  time,  is  proved  (i)  by  the  fact 
that  a  pressure  spot  always  responds  more  quickly  than 
a  pain  spot,  and  (2)  that  certain  parts  of  the  body  are 
sensitive  to  pressure  but  not  to  pain,  e.g.  the  inner  mem- 
brane of  the  cheek,  while  the  cornea  of  the  eye  always  re- 
sponds with  pain,  never  with  pressure,  no  matter  how 
slight  the  excitation.  Again,  (3)  certain  drugs  destroy 
one  sense  quality  and  leave  the  other  unaffected,  e.g. 


68 


ESSENTIALS    OF   PSYCHOLOGY 


cocaine  when  first  applied  destroys  the  sensitiveness  to 
pain  but  not  to  pressure;  a  rarer  drug,  saponin,  destroys 
sensitiveness  to  pressure  but .  not  to  pain.  It  is  now 


-list 


FIG.  ii.  —  Nerve  endings  in  skin  and  about  hair  follicles,  (c)  the  most  super- 
ficial  plexus  of  fibres  in  the  skin,  free  nerve  endings  still  nearer  the  surface ; 
(A)  the  hair  with  nerves  about  root.  (From  Barker,  Fig.  227,  after  Retzius.) 


SENSATION  69 

generally  held  that  pain  and  pressure  are  distinct  senses 
with  distinct  kinds  of  sensory  endings  in  the  skin. 

The  Organs  of  Cutaneous  Sensation.  —  Pressure  and 
pain  may  with  some  certainty  be  referred  to  particular 
sense-organs.  The  nerves  of  pressure  for  the  greater  part 
of  the  body  are  the  nerves  at  the  roots  of  the  hairs,  as 
illustrated  in  the  accompanying  diagram.  On  the  palms 
of  the  hands  and  the  soles  of  the  feet  where  hairs  are 
lacking,  the  organ  of  pressure  is  the  touch  corpuscle  of 
Meissner  that  is  found  in  the  pa- 
pillae of  the  skin.  (See  diagram.) 
The  nerves  of  pain  are  the  free 
nerve  ends  that  extend  into  the 
outer  skin.  They  too  may  be  seen 
in  Figure  1 1 .  That  pain  has  a  very 
superficial  organ  is  evident  from 
the  fact  that  an  acid  will  give  rise 
to  pain  before  it  affects  any  other 
of  the  sense-organs.  It  needs  only 
to  eat  into  the  most  superficial 
layer  of  the  skin,  and  the  sensa-  FlG.  I2._ Tactile  corpuscle 
tion  of  pain  is  aroused.  The  organs  of  Meissner  from  the  skin 

,  f  of  toe.      (N)    nerve    fibre. 

of  warmth  and  cold  have  not  been      (From  Barker,  Fig.   242, 
made  out  with  any  certainty.    The      after  Schiefferdecker.) 
skin,  then,  is  not  a  single  sense-organ,  but  a  mosaic  in 
which  four  separate  senses  may  be  distinguished,  each 
with  a  special   sense-organ.      These  are  pressure,  pain, 
warmth,  and  cold.     With  their  combinations  they  give 
rise  to  all  knowledge  of  the  outer  world  obtained  through 
the  skin. 
The  Gustatory  Sensations.  —  Most  closely  related  to 


70  ESSENTIALS   OF   PSYCHOLOGY 

the  sensations  from  the  skin  are  the  sensations  of  taste. 
As  every  one  knows,  the  chief  organ  of  taste  is  the  tongue. 
More  particularly  the  sense  endings  of  taste  are  to  be 
found  on  the  sides  of  the  foliate,  the  fungiform,  and  the 
circumvallate  papillae  on  the  tongue.  Essentially  the 
papillae  are  folds  of  skin  or  pits  on  the  surface  of  the 
tongue.  The  sense  endings  proper  are  the  taste  beak- 
ers which  are  arranged  along  the  sides  of  the  depressions 
formed  by  the  papillae.  The  beaker  itself,  as  may  be 
seen  from  the  diagram,  is  a  group  of  nerve  ends  inter- 
spersed with  supporting  cells.  The  whole  looks  not  unlike 
a  flower  bud.  The  papillae  are  scattered  fairly  thickly 
over  the  tip,  sides,  and  back  of  the  tongue.  They  can  be 
seen  on  the  tip  of  the  tongue  as  little  bright  red  depres- 
sions. Four  separate  taste  qualities  are  distinguished,  — 
sweet,  salt,  sour,  and  bitter.  The  different  qualities  can- 
not be  so  easily  connected  with  different  spots  on  the 
tongue  as  can  the  touch  qualities  with  spots  on  the  skin. 
The  taste-buds  are  well  concealed  in  the  papillae  and 
a  single  papilla  often  possesses  more  than  one  quality. 
It  is  assumed,  however,  that  each  taste  beaker  responds 
to  but  one  quality,  although  several  beakers  of  different 
kinds  may  be  present  in  the  same  papilla.  In  general, 
sweet  is  perceived  on  the  tip,  sour  on  the  sides,  of  the 
tongue,  bitter  on  the  back,  while  salt  is  pretty  evenly 
distributed.  At  the  most  this  arrangement  is  only  partly 
carried  out,  and  there  are  many  exceptions.  The  best 
evidence  for  the  doctrine  of  specific  energies  is  the  fact 
that  different  drugs  dull  or  destroy  different  tastes,  or 
at  least  affect  the  tastes  in  different  degrees.  Cocaine, 
for  example,  first  destroys  the  sensitiveness  to  bitter  and 


SENSATION 


affects  the  other  tastes  more  slowly.  Gymnemic  acid 
first  destroys  the  sensitiveness  to  sweet.  The  time  re- 
quired for  the  nerves  to  respond  is  also  different  for  each 


Subyemmul    cell 


Intergemmal  fibrils 

FIG.  13.  —  Taste-buds  and  endings  of  gustatory  nerves,  (a)  shows  taste  cells 
about  a  central  supporting  cell;  (6)  fibrils  around  and  between  the  taste- 
buds.  (From  Barker,  Fig.  348.) 

taste.  These  facts  together  seem  sufficient  to  justify  the 
statement  that  the  four  taste  qualities  have  each  a  special 
sort  of  taste  beaker,  although  several  different  sorts  of 
beakers  are  usually  found  in  a  single  papilla. 

Combination  of  Taste  with  Other  Sensations.  —  One 
may  be  inclined  to  question  the  statement  that  only  four 
taste  qualities  can  be  distinguished,  for  certainly  in  or- 


72  ESSENTIALS    OF   PSYCHOLOGY 

dinary  experience  there  seem  to  be  more  taste  qualities 
than  these.  This  objection  must  be  admitted.  The 
other  qualities  are,  however,  not  tastes  but  additions 
from  other  senses.  The  most  evident  are  the  ordinary 
cutaneous  sensations.  Temperature  seems  to  modify 
taste,  as  is  seen  in  the  peculiar  effect  of  the  cold  of  ice- 
cream or  the  heat  of  coffee.  Melted  cream  seems  to  have 
a  different  taste  from  the  frozen ;  cold  or  lukewarm  coffee, 
from  hot.  Roughness  or  smoothness  adds  a  quality  not 
easily  distinguished  from  taste,  as  in  the  difference  be- 
tween granulated  and  pulverised  sugar  and  in  many 
dainties  that  will  be  recalled  by  the  practical  housewife. 
By  far  the  most  important  additions  are  those  that  are 
made  by  smell.  Most  of  what  we  seem  to  taste  we  really 
smell.  All  of  the  delicate  tastes,  so-called,  are  largely 
odours  that  reach  the  sensory  region  in  the  nose  by  way  of 
the  inner  air  passages.  That  much  of  the  taste  of  food 
is  really  received  through  the  nose  is  evident  from  the 
fact  that  a  cold  destroys  nearly  all  taste.  Moreover,  if 
the  nostrils  be  closed,  substances  that  are  easily  dis- 
tinguished ordinarily  will  be  confused.  Cinnamon  is 
said  not  to  be  distinguishable  from  flour  under  these 
circumstances.  In  short,  in  what  is  ordinarily  called  taste 
we  have  a  mixture  of  the  four  simple  tastes  with  the 
qualities  of  cutaneous  sensation  and  with  odour.  The 
stimulus  for  taste  is  some  chemical  dissolved  in  a  liquid 
and  brought  into  contact  with  the  taste-buds  by  being 
caught  in  the  papillae.  A  substance  to  be  tasted  must  be 
dissolved  either  before  it  is  taken  into  the  mouth  or  by 
the  saliva. 

Sensations  of  Smell.  —  Of  the  sense  of  smell  we  know 


SENSATION 


73 


practically  nothing.  All  that  can  be  determined  is  that 
the  organ  of  smell  is  the  olfactory  membrane  in  the  upper 
nasal  cavity.  The  sense  nerves  are  simple  cells  with 
hairlike  projections  that  come  to  the  surface  of  the  mem- 
brane between  supporting  cells.  In  their  structure  they 


a 


FIG.  14.  —  Scheme  of  the  olfactory  apparatus  of  mammals.  (Z>)  the  olfactory 
membrane ;  (b)  the  olfactory  neurone.  Above  are  shown  the  more  central 
neurones  connecting  with  the  olfactory  lobe.  (From  Barker,  after  Ramon  y 
Cajal.) 

are  the  simplest  of  the  sense-organs.  The  stimulus  for 
odours  is  some  chemical  substance  carried  to  the  olfactory 
membrane  in  particles.  It  produces  some  chemical 
change  in  the  sense  ending  that  starts  the  nervous  im- 
pulse toward  the  brain. 

No  definite  answer  can  be  given  to  the  question  of  the 


74  ESSENTIALS   OF   PSYCHOLOGY 

number  of  different  organs  and  the  number  of  different 
olfactory  qualities.  Zwaardemaker  has  suggested  that 
there  are  nine,  but  his  results  cannot  be  accepted  as 
conclusive.  Certain  facts  connected  with  pathology  and 
with  fatigue  indicate  that  some  organs  are  responsive  to 
one  odour,  others  to  other  odours.  In  diseased  conditions 
a  patient  may  lack  one  class  of  odours  alone.  Also  the 
nose  maybe  fatigued  for  one  odour,  while  still  sensitive  to 
others.  After  one  has  smelled  camphor  for  some  time, 
alcohol  will  not  be  noticed,  but  iodine  will  still  have  its 
usual  effect.  While  these  experiments  are  suggestive  of 
the  presence  of  definite  sense-organs  for  different  odours, 
they  have  not  been  carried  far  enough  to  determine  the 
number  of  qualities.  The  uncertainties  of  science  are 
reflected  in  the  popular  speech.  There  are  no  names  for 
odours  other  than  those  of  the  objects  that  give  rise  to  them. 
The  difficulty  is  increased  by  the  fact  that  tactual  and 
taste  qualities  mix  with  the  olfactory.  The  sweet  odour 
of  chloroform  is  really  a  taste.  The  odour  of  ammonia 
is  largely  pain,  and  it  is  the  resulting  holding  of  the  breath 
that  gives  the  sense  of  suffocation.  Zwaardemaker  has 
a  class  of  nauseating  odours  that  receive  their  peculiar 
quality  from  the  incipient  retching  reflexes  excited  in  the 
throat.  Of  smell  we  know  only  that  the  organ  is  simple 
and  has  its  seat  in  the  upper  nasal  passages,  that  there  are 
distinguishable  qualities,  but  that  their  number  is  un- 
certain, and  that  smell  combines  with  taste  and  tactual 
impressions  to  produce  very  complex  fusions. 

Hearing.  —  The  first  of  the  so-called  higher  senses  is 
hearing.  Hearing  is  higher  in  its  importance  for  the 
mental  life,  in  the  degree  of  complexity  of  the  organ,  and 


SENSATION  75 

in  the  richness  of  its  qualities.  In  each  of  the  higher 
senses  we  must  consider  the  sense  excitation  at  three 
different  stages :  (a)  the  physical  stimulus,  (6)  the 
change  that  is  excited  in  the  sense-organ,  and  (c)  the 
resulting  conscious  qualities.  The  stimulus  for  hearing, 
physics  teaches,  is  vibration  in  the  air.  The  wave-lengths 
vary  in  three  ways:  in  the  rate  of  their  vibration,  in 
the  distance  through  which  the  particles  vibrate  or  the 
amplitude  of  vibration,  and  in  the  form  or  complexity  of 
the  wave.  The  rate  of  vibration  corresponds  to  the 
pitch  of  the  tone,  the  amplitude  corresponds  to  the  in- 
tensity of  the  tone,  and  the  form  to  the  timbre  or  tone 
colour.  The  form  of  the  wave  gives  the  tone  of  different 
instruments  a  different  character,  e.g.  the  C  of  the  violin 
differs  from  the  C  of  the  piano  only  in  its  wave  form. 

Structure  of  the  Ear.  —  The  organ  of  hearing  is  the 
ear.  The  ear  is  for  convenience  of  description  divided 
into  three  parts,  —  the  external  ear,  the  middle  ear  or 
drum,  and  the  inner  ear  or  labyrinth.  The  outer  ear 
is  the  trumpet  of  cartilage,  popularly  called  the  ear,  to- 
gether with  the  tube  that  extends  into  the  skull.  Its 
only  function  is  to  gather  the  sound-waves  and  bring 
them  to  the  drum.  The  middle  ear  extends  from  the 
membrane  of  the  drum  backward  to  the  bony  inner  ear. 
In  essentials  the  middle  ear  is  an  irregularly  shaped  hol- 
low in  the  skull  separated  from  the  outer  world  by  the 
drum,  and  connected  with  the  throat  by  the  Eustachian 
tube.  So  far  as  it  concerns  us,  it  is  a  cavity  across  which 
a  chain  of  three  bones,  the  hammer,  anvil,  and  stirrup, 
extends  from  the  membrane  of  the  drum  to  the  oval 
window  of  the  labyrinth.  The  drum  head  is  a  membrane 


76 


ESSENTIALS   OF   PSYCHOLOGY 


stretching  obliquely  across  the  opening  of  the  ear.  On 
its  inner  surface  is  the  handle  of  the  hammer.  The  head 
of  the  hammer  fits  into  the  anvil,  and  this  is  attached  to 
the  head  of  the  stirrup.  Each  bone  receives  its  name  from 
its  shape.  When  a  sound-wave  strikes  against  the  mem- 


FIG.  15. — Diagram  of  ear,  showing  relation  of  parts.  (M)  and  (G)  external 
ear;  (P)  middle  ear  with  small  bones;  (S)  cochlea;  (A)  auditory  nerve;  (R) 
Eustachian  tube.  (From  Professor  Calkins,  Fig.  15,  after  Martin-Czermak.) 

brane  of  the  drum,  the  membrane  is  forced  inward 
slightly,  and  this  inward  motion  carries  the  handle  of  the 
hammer  with  it.  The  hammer  and  the  other  bones  re- 
volve about  a  ligament  attached  to  the  top  of  the  middle 
ear.  The  impression  from  the  air  received  by  the  drum 
turns  the  bones  together  about  this  as  a  pivot,  and  the 
stirrup  communicates  the  motion  to  the  liquid  of  the 
inner  ear.  When  the  pressure  of  the  air  is  relaxed,  the 
membrane  of  the  drum  returns  to  its  original  position  or 


SENSATION 


77 


a  little  beyond  and  carries  with  it  the  chain  of  bones  and 
the  foot  of  the  stirrup.  The  foot  of  the  stirrup  fits  closely 
into  the  oval  window  of  the  inner  ear,  and  the  joint  is 
closed  by  a  delicate  membrane  that  makes  the  whole 
water-tight.  While  this  is  the  ordinary  course  of  stimu- 


FIG.  16.  —  Section  of  tube  of  cochlea.  (Lam.  sp.)  lamina  spiralis,  through  which 
the  nerve  passes;  (m.b.)  basilar  membrane  ;  (Org.  C.)  organ  of  Corti ;  (m.t.) 
tectorial  membrane.  (From  Professor  Calkins,  Fig.  17,  after  Foster.) 


78  ESSENTIALS    OF   PSYCHOLOGY 

lation,  high  tones  apparently  pass  through  the  bones  of 
the  head.  In  some  cases,  too,  hearing  is  normal  when 
the  bones  are  wanting  through  disease. 

The  Mechanics  of  the  Cochlear  Vibration.  —  The 
movement  of  the  stirrup  transmits  the  excitation  to  the 
inner  ear,  the  point  where  hearing  as  a  nervous  process 
begins.  The  auditory  portion  of  the  ear  is  the  cochlea. 
The  cochlea,  as  its  name  implies,  is  a  tube  coiled  up  like 
a  snail  shell  for  two  and  a  half  turns.  It  is  divided  down 
the  middle  by  a  ridge  of  bone  and  a  thin  membrane  known 
as  the  basilar  membrane.  Figure  16  shows  a  cross  section 
of  the  tube  of  the  cochlea.  One  of  the  first  questions  in 
connection  with  the  action  of  the  ear  is  how  it  is  possible 
for  the  vibrations  of  the  stirrup  and  of  the  oval  .window 
to  have  any  effect  upon  the  liquid  that  fills  the  cochlea  and 
the  inner  ear.  The  vibration  of  the  liquid  is  rendered 
possible  by  the  round  window  that  separates  the  liquid 
of  the  cochlea  from  the  air  of  the  middle  ear  at  a  point  on 
the  lower  side  of  the  tube  marked  Pt  in  the  diagrams. 
The  round  window  is  closed  by  a  delicate  membrane. 
When  the  oval  window  is  pressed  in,  the  round  window 
permits  the  liquid  in  the  cochlea  to  be  displaced.  The 
vibrations  of  the  outer  air  push  the  membrane  of  the  drum 
in  and  out.  The  chain  of  bones  is  made  to  vibrate  by 
the  drum  head.  The  stirrup  presses  against  the  liquid 
of  the  inner  ear,  and  this  is  permitted  to  vibrate  by  the 
delicate  membrane  of  the  round  window. 

The  Helmholtz  Theory  of  Hearing.  —  All  of  this  is 
only  preparation  for  the  excitation  of  the  nerve  of  hear- 
ing. The  nerve  of  hearing  ends  in  connection  with  the 
fibres  of  the  basilar  membrane.  The  exact  connection 


SENSATION  79 

between  the  nerve  fibres  and  the  fibres  of  the  basilar 
membrane  has  not  been  altogether  made  out,  but  nerve 
fibres  come  through  the  spiral  of  bone  and  end  in  con- 
nection with  hairs  on  both  sides  of  the  basilar  membrane 
and  upon  it.  They  probably  are  excited  in  some  way 
by  the  vibrations  of  the  basilar  membrane.  The  most 
generally  accepted  theory  of  hearing  was  suggested  by 
Helmholtz,  who  regarded  the  basilar  membrane  as  a 
series  of  strings  like  the  strings  of  a  piano.  Each  string 
is  tuned  to  some  one  of  the  audible  tones.  Whenever 
the  tone  to  which  a  string  is  tuned  is  represented  in  the 
vibrations  of  the  liquid  of  the  inner  ear,  that  string  is 
started  into  sympathetic  vibration.  The  vibration  of 
the  fibre  starts  a  nervous  impulse  in  the  nerve  connected 
with  it,  and  this  impulse  is  transmitted  to  the  brain 
through  a  series  of  neurones.  The  sensation  of  sound 
makes  its  appearance  upon  the  excitation  of  cells  in  the 
temporal  lobes  of  the  cortex.  The  process  of  exciting 
a  vibration  in  the  fibre  is  very  similar  to  that  which  ac- 
companies speaking  into  a  piano  when  the  keys  are  held 
down.  When  you  speak,  the  strings  that  are  tuned  to 
your  voice  are  excited  sympathetically  and  can  be  heard 
after  you  finish  speaking.  In  the  basilar  membrane  the 
fibres  are  said  to  number  between  eighteen  and  twenty 
thousand,  while  the  tones  that  can  be  distinguished  by 
the  ordinary  ear  have  been  computed  at  approximately 
eleven  thousand.  The  number  of  strings  is  then  suffi- 
cient for  the  tones  that  may  be  heard.  The  theory  of 
Helmholtz  is  strengthened  by  the  limited  number  of 
tones  that  may  be  appreciated.  The  upper  and  lower 
limit  of  hearing  may  be  explained  by  the  limited  number 


80  ESSENTIALS   OF   PSYCHOLOGY 

of  fibres.  The  lowest  tone  that  may  be  heard  has  ap- 
proximately sixteen  vibrations  per  second ;  the  highest 
varies  from  about  thirty  thousand  to  forty-five  thousand 
per  second.  Another,  strong  bit  of  evidence  for  the 
theory  is  that  after  death  there  have  been  found  in  in- 
dividuals, who  were  deaf  to  certain  notes  of  the  scale, 
regions  of  the  basilar  membrane  in  which  disease  had 
destroyed  the  fibres.  The  objections  to  the  Helmholtz 
theory  are  to  be  found  primarily  in  the  physical  improba- 
bility that  fibres  as  short  as  those  of  the  basilar  mem- 
brane, from  0.48  to  0.04  mm.  in  length,  should  be  able  to 
vibrate  in  sympathy  with  the  lower  tones  that  are  heard. 
Several  authorities  have  asserted  that  the  fibres  .are 
too  rigid  to  vibrate  to  faint  tones.  Whatever  the  ob- 
jections, the  Helmholtz  theory  is  the  one  at  present 
generally  accepted. 

Complex  Tones  and  Noises.  —  If  we  may  assume  that 
the  simple  tone  corresponds  to  the  excitation  of  a  single 
fibre  of  the  basilar  membrane,  it  seems  probable  that  the 
complex  tones  are  due  to  the  excitation  of  several  fibres. 
A  complex  tone  like  the  tone  of  the  piano  would  be  made 
up  of  one  tone,  the  fundamental,  and  of  others  of  a  rate 
two,  three,  four,  and  other  even  multiples  of  that  rate. 
The  timbre  of  the  tone  varies  with  the  number  and  char- 
acter of  the  overtones.  In  the  violin  tone  the  high  over- 
tones predominate;  in  the  piano  tone  the  overtones 
decrease  in  strength  as  they  increase  in  pitch.  In  the  ear 
each  of  these  overtones  is  taken  up  by  a  different  fibre  and 
is  carried  to  the  cortex  separately.  In  consciousness  they 
ordinarily  fuse  to  form  a  single  quality,  although  by  close 
attention  the  elements  may  be  distinguished.  What 


SENSATION  8 1 

then  in  the  air  is  fused  into  a  single  wave  of  characteristic 
form  is  analysed  by  the  basilar  membrane  into  its  sepa- 
rate elements  and  reunited  in  consciousness  to  form  a 
complex  tone.  Noises  of  the  continuous  kind  may  be 
regarded  as  very  complex  tones  made  up  of  many  vibra- 
tion rates  that  have  no  simple  arithmetical  relation  to 
each  other.  Each  is  received  by  a  separate  fibre  and 
transmitted  to  the  cortex,  where  the  result  is  a  jumble 
of  sensations.  The  single  crash  or  crack,  the  second  form 
of  noise,  arises  from  a  twitch  of  the  fibre  of  the  membrane 
that  does  not  persist  long  enough  to  give  a  full  tone.  Any 
tone  will  give  a  single  puff  of  noise  if  it  is  permitted  to 
affect  the  ear  during  but  two  full  vibrations.  In  either 
case  the  noise  is  heard  by  the  same  part  of  the  ear 
that  perceives  the  tone,  the  fibres  of  the  basilar  mem- 
brane in  the  cochlea. 

Summary.  —  In  short,  vibration  in  the  air  is  received 
by  the  membrane  of  the  drum  and  is  transmitted  to  the 
oval  window  through  the  chain  of  small  bones.  At  the 
oval  window  the  oscillations  of  the  bones  produce  vibra- 
tions in  the  liquid  of  the  inner  ear.  The  several  tones  are 
received  by  the  different  fibres  of  the  basilar  membrane 
attuned  to  them.  The  vibration  of  the  fibres  excites 
a  change  in  the  nerve  that  is  connected  with  it,  and  the 
nervous  impulse  is  carried  to  the  cortex  where  sensation 
arises.  It  is  still  a  question  whether  we  are  to  assume 
that  each  fibre  has  its  own  quality  of  sensation  and  that 
there  are  therefore  eleven  thousand  distinct  sensations 
and  eleven  thousand  distinct  sorts  of  nerve  fibre,  or 
whether  the  different  fibres  are  grouped  in  some  way  in 
larger  classes.  The  objection  to  the  assumption  of  so 


82  ESSENTIALS   OF   PSYCHOLOGY 

many  distinct  nerve  processes  and  sensations  is  that  it 
gives  hearing  a  disproportionate  number  of  qualities 
when  compared  with  the  other  senses.  More  cogent  is 
the  argument  that  notes  an  octave  apart  seem  more  alike 
than  notes  within  the  octave.  Two  C's  are  more  likely 
to  be  confused  than  C  and  G,  or  C  and  B.  But  if  we 
assume  that  there  are  fewer  simple  primary  qualities  than 
there  are  distinguishable  tones,  there  is  as  yet  no  agree- 
ment as  to  what  these  primary  qualities  are,  or  how  many 
there  are  of  them. 

Visual  Sensations.  —  By  far  the  most  important  sense 
is  sight.  We  trust  vision  above  the  other  senses  in  per- 
ception, and  most  people  think  in  images.  When  we 
recall  an  object,  we  remember  how  it  looks  rather  than 
any  other  of  its  sensory  qualities.  In  discussing  sight 
we  have  again  to  consider  the  three  stages  of  the  visual 
process,  —  external  stimulus,  sense-organ,  and  sensa- 
tion. There  is  in  vision  rather  greater  dissimilarity  be- 
tween the  different  stages  than  in  hearing.  The  physical 
stimulus  is  a  vibration  in  the  hypothetical  ether.  The 
physicist  tells  us  that  the  ether  vibration  varies  in  the 
same  three  ways  as  the  sound  vibration.  Changes  in 
rate  or  in  length  of  the  wave  give  quality ;  changes  in  the 
amplitude  of  vibration  give  intensity;  while  changes  in 
form  or  complexity  give  what  we  know  as  degrees  of 
saturation,  —  the  greys  and  mixtures  of  greys  with  colours. 
The  rate  or  length  corresponds  to  colour.  Red  has  a 
wave-length  of  some  800-833  A1/*  (thousandths  of  thou- 
sandths of  a  millimetre),  violet  a  wave-length  of  less  than 
half,  or  380-400  A1/*.  The  colours  between  have  inter- 
mediate wave-lengths.  Change  in  amplitude  gives  vary- 


SENSATION  83 

ing  brightnesses,  from  black  through  the  colours  (what 
colour  depends  upon  the  wave-length  -  of  the  light) 
to  white.  Mixtures  of  light-waves  give  white  or  grey, 
and  intermediate  qualities  give  spectral  colours  according 
to  the  wave-lengths  that  are  mixed.  In  any  case  it  is 
evident  that  the  qualities  of  the  things  as  we  see  them 
are  not  at  all  like  the  vibrations  that  the  physicist  as- 
sures us  cause  them.  There  is  nothing  in  the  colours  to 
indicate  that  violet  is  a  more  rapid  vibration  than  red. 
There  are  many  disparities  even  in  relations.  Red  and 
violet  are  more  unlike  physically,  but  the  sensations  are 
more  alike  than  those  of  red  and  yellow,  or  of  red  and 
any  of  the  intermediate  colours  that  are  nearer  red  in 
vibration  rate. 

The  Structure  of  the  Eye.  —  The  key  to  the  difference 
between  the  physical  stimulus  and  the  qualities  of  colour 
must  lie  in  the  eye.  That  vibrations  of  different  lengths 
give  similar  sensations  must  be  due  to  the  similarity  of 
the  physiological  processes  that  they  arouse  in  the  retina. 
The  eye  can  be  best  understood  if  it  is  compared  to  a 
camera.  Three  parts  are  essential  to  a  camera :  the  box 
or  container,  the  lens,  and  the  sensitive  plate.  The  box 
or  frame  of  the  eye  is  to  be  found  in  the  sclerotic  coat, 
the  tough  membrane  that  holds  the  parts  together,  and 
is  kept  distended  into  a  sphere  by  the  pressure  of  the 
liquid  within.  The  organ  is  mounted  in  its  socket,  a 
conical  hollow  in  the  skull.  It  is  held  in  its  socket  by 
threads  of  connective  tissue  and  is  turned  by  three  pairs 
of  muscles  that  enable  it  to  revolve  through  a  wide  arc. 
Within  the  sclerotic  coat  is  first  the  choroid  coat  that 
nourishes  the  eye  and  has  some  nerves  and  muscular 


84 


ESSENTIALS   OF   PSYCHOLOGY 


fibre,  and  within  that  is  the  retina  that  corresponds  to 
the  sensitive  plate.  The  lens  system  of  the  eye  is  made 
up  of  two  parts,  the  cornea  and  the  crystalline  lens. 
The  cornea  is  really  only  a  part  of  the  sclerotic  coat  that 


FIG.  17.  —  Section  of  eye.  (Scler.)  sclerotic  coat ;  (Chor.)  choroid ;  (Ret.)  retina, 
(Opt.)  optic  nerve ;  (Fov.  c.)  fovea ;  (Pr.  cil.)  the  ciliary  muscle  or  ciliary  process, 
which  adjusts  the  lens  for  different  distances;  (conj.)  conjunctiva.  (Cam.  ant.) 
is  the  anterior  chamber,  filled  with  the  aqueous  humour :  (corpus  vitreum)  is  the 
vitreous  humour  that  fills  the  posterior  chamber.  (From  Angell's  '  Psychol- 
ogy,' Fig.  47.) 


SENSATION  85 

projects  slightly  and  forms  in  consequence  a  stronger 
lens.  The  structure  of  the  tissue  is  sufficiently  changed 
to  make  the  cornea  transparent  instead  of  white  and 
opaque  as  is  the  sclerotic  coat.  The  lens  is  just  back  of 
the  iris,  the  coloured  portion  of  the  eye.  It  is  attached  to 
the  choroid  coat  by  a  ligament,  the  suspensory  ligament. 
That  in  turn  is  connected  with  the  ciliary  muscle  which 
forms  part  of  the  choroid  coat.  In  front  of  the  lens  lies 
the  anterior  chamber  filled  with  a  liquid  much  like  water, 
as  its  name,  aqueous  humour,  implies.  Back  of  the  lens 
is  the  posterior  chamber,  filled  with  the  jellylike  vitreous 
humour. 

The  Eye  as  an  Optical  Instrument.  —  The  rays  of  light 
are  bent  at  the  front  surface  of  the  cornea,  and  at  the  two 
surfaces  of  the  lens.  The  whole  system  has  the  same 
effect  as  if  the  light  came  through  a  single  pinhole  15  mm. 
in  front  of  the  retina  or  7  mm.  back  of  the  cornea. 
The  size  of  the  image  of  any  object  thrown  upon 
the  retina  will  be  found  by  drawing  a  line  from  the 
sides  of  the  object  to  the  retina  through  this  nodal  point 
where  the  pinhole  might  be.  One  extremely  important 
function  of  the  lens  is  the  accommodation  or  focussing 
of  the  eye.  A  camera  that  cannot  be  adjusted  for  dif- 
ferent distances  is  of  little  value  since  pictures  could  be 
taken  at  one  distance  only.  An  eye  with  a  fixed  system 
of  lenses  could  see  objects  at  but  one  distance.  The  eye 
is  accommodated  for  different  distances  by  changing 
the  shape  of  the  lens.  The  lens  is  relatively  flat  when  one 
is  looking  at  a  distant  object,  but  becomes  thick  and  well 
rounded  when  one  looks  at  a  near  object.  This  thicken- 
ing of  the  lens  may  be  seen  if  one  will  look  across  the  eye 


86  ESSENTIALS   OF   PSYCHOLOGY 

of  another.  When  the  eye  is  adjusted  for  distance, 
the  iris  is  flat ;  when  it  is  focussed  on  a  finger  held  close, 
the  lens  may  be  seen  to  push  out  the  iris.  The  shape 
of  the  lens  is  changed  by  the  contraction  of  the  ciliary 
muscle.  The  muscle  contracts  and  permits  the  lens  when 
looking  at  the  near  object  to  take  on  its  normal,  rather 
round  shape.  When  the  muscle  is  relaxed,  the  lens  is 
tightly  stretched  by  the  suspensory  ligament  and  so 
becomes  long  and  thin.  (See  diagram.)  Another  ad- 
justment of  the  eye  that  may  be  mentioned  is  the  change 
in  the  size  of  the  pupil.  The  iris  is  really  a  part  of  the 
choroid  coat  that  might  have  been  drawn  away  from  the 
attachment  to  the  cornea.  The  pupil  is  the  hole  in  the 
iris.  When  the  eye  is  in  the  dark,  the  muscles  that  hold 
the  pupil  open  are  contracted ;  when  the  light  is  bright, 
the  sphincter  of  the  pupil  contracts,  the  other  muscles  re- 
lax, and  the  pupil  becomes  small.  The  dilation  permits 
a  larger  amount  of  light  to  enter  the  eye,  the  contraction 
protects  the  eye  against  too  bright  light. 

The  real  seeing  portion  of  the  eye  is  the  retina.  The 
retina  is  a  part  of  the  brain  that  in  the  course  of  develop- 
ment has  come  to  the  surface.  It  is  made  up  of  three 
layers  of  neurones.  The  structures  that  receive  the  light 
are  the  rods  and  cones.  These  are  farthest  away  from  the 
light,  nearest  the  choroid  coat.  There  is  an  intermediate 
and  an  inner  neurone  layer.  .The  various  layers  have 
synapses  over  which  the  impulse  may  be  transmitted. 
The  axones  of  the  inner  layer  of  so-called  large  ganglion 
cells  combine  to  form  the  optic  nerve.  In  exciting  the 
eye  a  ray  of  light  traverses  the  outer  neurones  as  a  phys- 
ical impulse  (vibration  in  the  ether),  strikes  upon  the 


SENSATION 


rods  and  cones,  is  there  transformed  into  a  nervous  im- 
pulse and  transferred,  first  to  the  intermediate  bipolar 


FIG.  1 8.  —  Schematic  diagram  of  the  nervous  structure  of  the  retina.  (/)  the 
layer  of  pigment  cells ;  (//)  the  rods  and  cones;  (VI)  the  bi-polar  cells;  (IX) 
the  large  ganglion  cells ;  and  (X)  the  axones  that  later  unite  to  constitute  the 
optic  nerve.  (From  Professor  Calkins,  Fig.  14,  after  Howell.) 


t 
88  ESSENTIALS   OF   PSYCHOLOGY 

cells,  then  to  the  outermost  large  ganglion  cells,  and 
finally  is  carried  back  to  the  brain.  In  this  way  it  goes 
back  as  a  nervous  impulse  over  part  of  the  course  that 
it  originally  traversed  as  a  light-wave. 

At  the  centre  of  the  retina  is  a  small  depression  or  pit 
known  as  the  fovea.  In  and  about  this  the  retina  has 
a  yellow  pigment  which  gives  the  name,  yellow  spot,  to 
the  general  region.  Owing  to  the  pit  the  light  suffers  less 
absorption  than  at  other  portions  of  the  retina  in  reaching 
the  sensitive  structures.  In  the  fovea  there  are  only 
cones,  and  they  are  more  closely  set  than  elsewhere. 
The  lack  of  absorption  and  the  slight  distance  that  sep- 
arates the  cones  make  the  fovea  the  point  of  clearest 
vision.  From  the  fovea  outward  the  cones  decrease  in 
number  until  on  the  periphery  they  practically  disappear. 
The  entrance  of  the  optic  nerve  is  not  provided  with  rods 
and  cones  and  in  consequence  is  not  sensitive  to  light. 
It  is  what  is  known  as  the  blind  spot.  We  know,  then, 
that  the  vibrations  in  the  ether  come  to  the  rods  and  cones 
in  the  deepest  coat  of  the  retina.  There  in  some  way 
they  are  transformed  into  nerve  impulses,  pass  from  one 
to  another  of  the  three  neurones  in  the  eye,  and  then  to  the 
basal  ganglia  and  cortex. 

Vision  a  Photo-chemical  Process.  —  The  first  question 
of  function  is  how  ether  vibrations  are  changed  to  nerve 
impulses.  An  analogy  for  this  is  found  in  the  action  of 
light  in  producing  chemical  changes  in  the  photographic 
plate.  It  is  possible  to  observe  directly  changes  of  this 
kind  in  the  visual  purple  found  in  the  outer  portions  of 
the  rods.  This  bleaches  when  exposed  to  light  and 
becomes  purple  when  the  eye  is  kept  in  the  dark.  The 


SENSATION  89 

bleaching  of  the  visual  purple  has,  however,  only  an  in- 
direct relation  to  seeing.  The  increased  sensitiveness 
that  comes  after  a  long  period  in  the  dark  is  due  to  the 
effect  of  the  visual  purple,  but  ordinary  daylight  vision 
is  practically  unaffected  by  it. 

Primary  Colours  and  their  Combinations.  —  For  an 
explanation  of  the  action  of  the  retina  we  are  compelled 
to  rely  upon  indirect  evidence  obtained  by  experiment 
and  observation.  We  may  be  guided  again  by  the  doc- 
trine of  specific  energies.  There  are  apparently  six 
specific  qualities  from  which  all  visual  processes  must  be 
derived.  These  are  the  two  brightnesses,  white  and  black, 
and  four  colours,  red,  yellow,  green,  and  blue.  The  spec- 
tral qualities  and  purple  are  obtained  from  the  four 
primary  colours.  Orange  is  a  combination  of  red  and 
yellow  and  may  be  produced  by  combining  red  and  yellow 
lights  in  the  right  proportions.  When  a  spectrally  pure 
ray  of  orange  light  falls  upon  the  retina,  it  excites  the 
two  responses  red  and  yellow  in  different  degrees,  and 
the  results  of  the  two  physiological  processes  combine 
in  the  brain  or  in  consciousness  to  produce  the  single 
sensation  of  orange.  Similarly,  yellow  and  green  com- 
bine to  produce  canary  yellow,  green  and  blue  to  give 
robin's  egg  blue  and  other  shades.  Finally  the  circle 
is  completed  by  the  fact  that  red  combines  with  blue  to 
give  first  indigo,  then  violet  and  the  whole  series  of  purples 
that  complete  the  circle  between  the  ends  of  the  spectrum. 
It  is  interesting  to  note  that,  while  all  the  other  mixed 
colours  may  be  produced  either  by  having  a  single  pure 
light-wave  fall  upon  the  retina  or  by  combining  two  lights 
in  proper  proportions,  the  purples  can  be  induced  only  by 


9o 


ESSENTIALS   OF   PSYCHOLOGY 


combining  lights.  There  is  no  single  ether-wave  that 
gives  a  purple  colour.  Nevertheless,  purple  is  quite  as 
unitary  in  sensation  as  any  of  the  colours  that  are  pro- 
duced by  a  single  wave-length. 

The  colours  and  their  relations  to  the  simple  colours  may 
be  illustrated  by  a  square.  (See  diagram,  Fig.  19.)  The 
corners  represent  the  simple 
colours,  the  sides  the  combina- 
tions that  may  be  produced 
from  them.  With  each  of  these 
colours  a  brightness  is  combined. 
These  series  of  brightnesses  ex- 
tend from  black  to  white.  All 
wave-lengths  excite  the  bright- 
nesses, and  the  quality  of  the 
brightness  depends  upon  the 
amplitude  of  the  wave,  not  at 
all  upon  the  length.  iEach  of 
the  waves  at  a  given  intensity 
excites  brightness  in  very  slight 
degree,  colour  in  larger  amount. 
A  faint  red  light  appears  black 
because  it  affects  the  brightness 
organ  only ;  as  it  grows  brighter 
it  looks  first  dark  brown,  then  dark  red,  then  red,  then 
bright  red  and  pink  in  order,  and  with  very  great  in- 
tensities approaches  white.  Where  the  colour  is  present 
in  greatest  proportion,  it  is  said  to  be  saturated.  As 
the  grey  becomes  more  and  more  prominent,  it  is  said 
to  be  less  and  less  saturated. 
Complementary  Colours.  —  One  result  of  mixing 


FIG.  ig.  —  Colour  pyramid. 
(From  Titchener  :  '  Text-book 
of  Psychology,'  Fig.  15.) 


SENSATION  QI 

colours,  the  phenomenon  of  complementary  colours, 
must  be  taken  into  account  before  the  full  effects  of  light 
can  be  stated.  When  colours  at  opposite  corners  of  our 
colour  square  are  mixed  in  suitable  proportions,  they  give, 
not  an  intermediate  colour,  but  brightness.  Apparently 
the  complementary  colours  produce  exactly  opposite 
effects  upon  the  substance  that  is  sensitive  to  them: 
each  destroys  the  effect  of  the  other.  When  they  thus 
neutralize  each  other,  the  only  effect  is  to  excite  the  organ 
of  brightness,  and  the  result  is  white,  grey,  or  black, 
according  to  the  intensity  of  the  colours.  When  any 
two  colours  are  mixed,  there  is  always  partial  cancella- 
tion, and  the  resulting  colours  are  always  less  saturated 
than  the  components  would  be.  If  all  the  colours  of 
the  sun's  rays  are  mixed,  the  components  all  cancel  each 
other  and  the  result  is  the  white  or  slightly  yellowish 
daylight.  We  may  represent  the  greys  upon  our  dia- 
gram by  a  line  through  the  centre  of  the  square  extending 
above  and  below.  The  fact  that  each  light  ray  at  a 
slight  intensity  excites  only  brightness  may  be  indicated 
by  connecting  each  corner  of  the  square  with  the  ends 
of  the  line.  It  seems  probable,  too,  that  the  lights  in  max- . 
imum  intensity  excite  only  the  brightness  organ.  This 
is  represented  by  connecting  each  corner  of  the  square 
with  the  top  of  the  brightness  line  as  well.  Thus  drawn, 
every  point  on  the  pyramid  inside  and  out  represents 
some  colour  or  shade,  and  all  visual  qualities  are  repre- 
sented. 

After  Images  and  Colour-blindness.  —  The  fact  of 
complementariness  makes  it  probable  that  the  colour 
qualities  of  each  pair  have  their  seat  in  a  single  organ. 


92  ESSENTIALS    OF    PSYCHOLOGY 

This  assumption  is  furthered  by  other  facts  of  vision. 
Thus  if  one  looks  at  any  colour  or  any  brightness  for  a 
few  seconds  and  then  looks  at  another  surface,  the  com- 
plementary colour  will  be  seen.  Red  gives  an  after- 
image of  green,  yellow  an  after-image  of  blue,  and  vice 
versa.  It  is  assumed  that  the  after-image  is  due  to  the 
fact  that  when  the  organ  is  excited  in  one  way,  recovery 
from  the  excitation  gives  the  complementary  colour. 
Even  stronger  evidence  for  assigning  each  pair  to  a  single 
organ  is  derived  from  the  phenomenon  of  colour-blindness 
and  the  distribution  of  the  colours  upon  the  retina. 
Individuals  are  found  who  lack  altogether  the  red  and 
green  components  of  colour,  but  none  who  can  be  shown 
to  be  altogether  lacking  in  one  alone.  If  one  is  colour- 
blind, it  is  either  to  red  and  to  green  or  to  all  colours,  never 
to  red  or  to  green  alone.  The  phenomena  of  colour- 
blindness are  present  in  every  normal  eye.  In  a  band 
about  the  centre  red  and  green  cannot  be  seen.  Beyond 
this  band  the  eye  is  totally  colour-blind;  only  black  and 
white  are  appreciated  there.  This  outer  colour-blind- 
ness may  be  demonstrated  by  moving  a  small  bit  of  paper 
of  some  colour  out  toward  the  periphery  of  the  field  of 
vision  while  the  eye  is  kept  fixed  upon  a  point.  If  the 
colour  be  primary,  it  will  turn  to  grey  when  it  changes 
at  all  in  quality.  If  it  be  a  composite  colour  like  orange, 
it  will  change  first  to  yellow  and  then,  when  it  gets  beyond 
the  blue-yellow  zone,  to  grey.  These  phenomena  taken 
together  indicate  that  colour  qualities  are  connected  in 
pairs  with  their  organs.  Red  and  green  have  a  single 
organ  as  have  blue  and  yellow,  black  and  white.  The 
process  that  gives  red  is  in  some  way  opposed  to  the 


SENSATION  93 

process  that  gives  green.  Yellow  is  opposed  to  blue  in  the 
same  way.  There  is  less  evidence  that  black  and  white 
are  opposed,  but  that  is  still  the  usual  assumption.  When 
opposed  processes  are  excited,  they  destroy  each  other; 
when  one  is  excited  and  the  stimulus  withdrawn,  the 
other  colour  makes  its  appearance.  When  one  colour  dis- 
appears or  is  not  found,  the  other  also  is  not  present. 
No  altogether  satisfactory  explanation  of  what  the  change 
is,  or  of  what  the  nature  of  the  opposition  may  be,  has 
been  found,  but  that  the  process  is  a  chemical  one,  and  that 
the  two  directions  are  opposed  is  generally  accepted. 

Colour  Contrast.  • —  One  other  phenomenon  that  is 
due  to  the  opposed  direction  of  the  processes  is  the  phe- 
nomenon of  contrast.  If  two  complementary  colours  are 
side  by  side,  each  becomes  brighter  because  of  the  pres- 
ence of  the  other.  If  a  colour  is  seen  against  a  grey  back- 
ground, it  will  be  surrounded  by  a  fringe  of  the  comple- 
mentary colour.  Red  will  give  a  green,  blue  a  yellow, 
and  so  on.  The  contrast  effect  may  be  observed  if  a 
small  patch  of  grey  paper  be  put  on  a  coloured  surface. 
The  effect  will  be  increased  if  a  bit  of  translucent  paper 
be  put  over  the  colour  and  the  square  of  grey.  Contrast 
colours  are  also  very  clearly  seen  when  a  shadow  is  thrown 
upon  a  coloured  field  as  when  two  shadows  of  the  same 
object  are  cast  by  different  coloured  lights.  The  expla- 
nation of  contrast  is  probably  to  be  found  in  the  opposi- 
tion between  the  chemical  processes  excited  by  comple- 
mentary colours.  When  a  surface  is  stimulated  by  one 
light,  the  opposite  process  is  produced  in  the  surrounding 
areas  of  the  retina.  One  other  fact,  upon  which  there  is 
agreement,  is  that  there  are  different  organs  for  faint  and 


94  ESSENTIALS   OF   PSYCHOLOGY 

for  bright  or  moderate  lights.  The  faint  lights  affect 
the  rods  alone,  and  the  brighter  lights,  the  cones.  The 
light  that  is  noticed  at  night  after  one  has  been  long  in 
the  open  excites  the  rods.  The  increase  in  sensitiveness 
of  the  eye  after  long  adaptation  to  the  dark  comes  from 
the  increase  in  the  amount  of  visual  purple  that  sensitises 
the  retina,  as  sensitive  plates  may  be  increased  in  sensi- 
tiveness by  the  application  of  proper  chemicals. 

Summary  of  the  Facts  of  Vision.  —  In  brief  we  may 
assume  that  there  are  six  processes  in  the  retina  from 
which  all  of  the  visual  qualities  are  compounded.  These 
six  qualities  are  grouped  in  pairs,  red  and  green,  blue  and 
yellow,  and  black  and  white,  and  each  pair  finds  physi- 
ological explanation  in  opposed  processes  in  the  same 
substance.  When  the  two  processes  are  excited  simul- 
taneously, there  is  no  effect  upon  the  colour,  but  only  the 
resulting  effect  upon  the  brightness  organ.  When  one 
process  has  been  aroused,  its  opposite  succeeds  it  after  a 
brief  persistence  of  the  first.  In  colour-blindness  the 
red-green  organ  is  most  often  lacking.  Next  most  fre- 
quently wanting  is  the  yellow-blue  organ,  while  the  black- 
white  organ  is  always  present  unless  the  eye  be  totally 
blind.  It  is  interesting  to  note  that  the  manifold  wave- 
lengths in  ether  affect  the  retina  in  but  six  .different 
ways.  What  is  lost  in  complexity  in  the  retina  is  got 
back  with  interest  in  consciousness.  The  six  processes 
by  their  combinations  give  rise  to  from  thirty  to  fifty 
thousand  distinguishable  qualities.  It  is  interesting  to 
note  that  the  physiologically  complex  colours  are  little 
if  any  less  simple  as  conscious  qualities  than  the  simple 
physiological  colours.  So  true  is  this  that  just  what  are 


SENSATION  95 

the  simple  physiological  qualities  is  still  a  matter  of  dis- 
pute. Each  colour  theory  has  a  different  set  of  primary 
colours  and  the  only  hope  of  agreement  depends,  not 
upon  introspective  analysis,  but  upon  physiological 
experiment. 

Kinaesthetic  Sensations.  —  In  addition  to  the  tradi- 
tional five  senses  of  man,  many  new  sense  qualities  and 
sense-organs  have  been  discovered  in  the  last  few  years. 
Most  important  of  these  is  the  sensation  complex  that 
tells  us  of  the  movement  of  the  body,  of  weight  and  resist- 
ance. When  one  moves  the  hand,  one  knows  at  once 
the  amount  and  direction  of  the  movement  even  with 
the  eyes  closed.  Pathological  cases  are  found,  however, 
in  which  the  patient  is  unconscious  of  movement  and  of 
weight.  When  he  moves,  he  has  no  idea  that  he  has 
moved,  and  he  has  no  idea  of  the  position  of  his  members 
when  they  are  at  rest.  These  cases  emphasise  the  fact 
that  the  normal  man  must  have  some  special  sense- 
organ  for  the  detection  of  movements.  Investigation 
has  shown  that  the  sensations  come  from  organs  in  the 
muscles  and  tendons.  In  the  tissue  of  muscles  and 
tendon  are  sense-organs  not  unlike  some  of  the  organs 
found  in  the  skin.  When  the  muscle  is  contracted,  the 
cells  of  the  muscle  become  shorter  and  thicker.  This 
change  exerts  pressure  upon  and  stimulates  the  sensory 
ends  between  the  muscle  cells.  For  example,  whenever 
the  arm  is  moved,  there  is  a  contraction  in  one  set  of 
muscles  and  a  relaxation  in  the  opposing  set.  In  one  set 
of  muscles  the  sense-organs  will  be  compressed,  in  the 
other  set  the  pressure  will  be  relaxed.  Each  movement 
and  each  position  has  a  complex  of  increasing  and 


96  ESSENTIALS   OF   PSYCHOLOGY 

decreasing  stimulations  which  is  characteristic  for  that 
movement  in  quality  and  intensity.  Strains  and  weights 
when  the  arm  is  not  moved  reveal  themselves  in  similar 
pressure  exerted  upon  the  sense-organs  of  the  tendons 
in  addition  to  those  of  the  muscle-organs.  It  is  by  these 
organs  that  we  become  aware  of  the  fundamental  physical 
properties  of  the  world,  —  of  motion,  of  energy,  and  of 
mass. 

The  Static  Sense.  —  One  of  the  most  interesting  of  the 
recently  discovered  sense-organs  is  the  organ  of  the  static 
sense  found  in  the  semicircular  canals  and  neighbouring 
organs  of  the  ear.  Hairs  project  into  the  liquid  of  the  semi- 
circular canals.  When  the  liquid  is  disturbed  by  the 
motion  of  the  body,  the  hairs  are  moved  and  they  in  turn 
excite  the  nerves  connected  with  them.  These  impulses 
are  transmitted  to  the  motor  neurones  that  control  the 
movement  of  the  body,  and  movements  are  made  that 
adjust  the  members  to  the  new  position  or  bring  the  body 
back  to  the  upright.  When  the  organs  of  the  labyrinth 
are  injured,  proper  motor  adjustments  are  difficult  or 
impossible.  An  animal  with  injured  semicircular  canals 
will  not  be  able  to  stand,  or  at  least  to  stand  straight. 
When  the  organs  are  lacking  in  man,  reflex  eye-move- 
ments are  wanting.  It  is,  perhaps,  a  question  whether 
the  static  sense  is  a  real  sense,  for  we  become  aware  of  its 
action  only  indirectly  through  the  movements  it  induces 
or,  when  the  excitation  is  more  intense,  by  the  disturb- 
ances of  the  alimentary  tract  that  give  rise  to  the  sensa- 
tion of  giddiness.  When  still  more  intense,  the  stimuli 
from  these  organs  give  rise  to  the  more  active  phenome- 
non of  vomiting  involved  in  sea-sickness,  for  example. 


SENSATION  97 

What  the  immediate  quality  of  the  sensation  from  the 
static  sense  may  be,  is  not  known. 

Organic  Sensations.  —  Many  other  sense-organs  and 
sense  qualities  are  known  less  definitely.  The  sensations 
from  them  have  not  been  satisfactorily  analysed,  and  their 
organs  are  not  well  known  from  physiological  experi- 
ments. We  ordinarily  group  them  into  a  single  mass 
of  organic  sensation.  Of  these  hunger  is  known  to  have 
its  seat  in  the  membranes  of  the  stomach,  thirst  in  the 
upper  throat  or  back  of  the  mouth.  It  is  probable  that 
there  are  special  organs  that  inform  us  of  circulatory  dis- 
turbances, of  the  respiratory  processes,  and  of  many  others 
less  well  distinguished.  One  is  aware  of  feeling  well  or 
of  feeling  ill,  and  if  one  will  examine  the  experience  more 
closely,  vague  sensory  qualities  may  be  analysed  from 
the  mass.  It  is  to  be  hoped  that  these  complexes  of 
organic  sensation  may  some  day  be  analysed  and  their 
sense-organs  determined.  Until  that  time  we  can  merely 
refer  to  the  mass  and  say  nothing  more. 

Summary  of  Sense  Qualities.  —  If  we  sum  up  the 
results  of  this  discussion  of  the  qualities  of  sensation,  we 
find  that  there  are  relatively  few  simple  qualities  received 
from  sense-organs  and,  regarded  from  the  physiological 
side,  relatively  few  sorts  of  sense  endings.  A  table  will 
show  the  number  of  qualities  from  each  sense. 


Qualities  from  the  skin 4 

Qualities  of  taste 4 

Qualities  of  smell uncertain  (9  ?) 

Qualities  of  hearing uncertain  (11,000?) 

Qualities  of  sight 6 

Qualities  of  kinsesthetic  sensations  ....       i  or  2 
Qualities  of  organic  sensations    .     .     .     .     10  or  12  (?) 


98  ESSENTIALS   OF   PSYCHOLOGY 

In  total  there  are  but  forty  or  fifty  different  sorts  of  nerve 
ends  from  which  all'the  varieties  of  our  conscious  qualities 
are  derived.  We  might  obtain  a  much  larger  number 
if  we  considered  the  number  of  qualities  that  could  be 
recognised  by  unaided  observation  as  distinct  in  con- 
sciousness. Then  we  should  have  the  total  11,000  tones, 
some  40,000  colour  qualities,  unlimited  tactual  qualities, 
the  different  complexes  of  taste  and  smell,  one  for  each 
recognisable  object,  —  to  say  nothing  of  the  vast  number 
of  organic  complexes  that  change  with  each  of  our  moods, 
and  with  our  condition  of  health.  Enumeration  on  this 
basis  has  never  been  attempted  except  for  sight  and 
sound,  but  it  is  probable  that  the  other  senses  give  similar 
large  numbers  of  sensations  or  complexes  of  sensations. 

One  other  aspect  or  attribute  of  sensation  important 
in  practice  is  intensity.  The  intensity  of  sensation  is 
dependent  upon  the  intensity  of  the  stimulus.  The 
more  energy  acts  upon  the  sense-organ,  the  greater  the 
intensity.  While  intensities  play  a  very  large  part  in  our 
life,  they  are  not  easily  described  or  even  thought  of  in 
absolute  terms.  They  cannot  be  easily  remembered. 
We  have  no  accurate  names  for  the  degrees  of  intensity 
in  our  non-scientific  vocabulary.  Pounds  and  kilograms, 
ergs  and  horse-power,  are  obviously  artificial  units  and 
correspond  to  nothing  that  we  can  picture  easily.  For 
everyday  usage  very  heavy,  very  bright,  or  very  painful 
are  as  far  as  one  can  go  in  giving  accurate  descriptions. 
The  difficulty  in  description  and  discussion  is  all  the  more 
marked  because  experiments  show  that  there  is  no  direct 
relation  between  the  intensity  of  the  physical  stimulus 
and  the  resulting  consciousness.  As  nearly  as  one  can 


SENSATION  99 

make  out  a  thousand  ounces  do  not  give  a  thousand  times 
as  much  weight  sensation  as  one  ounce.  Sensations 
seem  to  increase  in  amount  very  much  more  slowly  than 
stimuli  increase  in  intensity,  —  if  one  may  speak  of  the 
amount  of  sensation  at  all.  Intensities  of  sensation  can- 
not be  described  by  words  as  we  describe  qualities  of 
sensation,  and  they  cannot  be  measured  by  measuring 
the  intensity  of  the  physical  stimulus  and  assuming  that 
the  sensation  will  harmonise  with  that.  Both  the  simple 
methods  of  approach  fail  us. 

The  attempt  to  discover  some  means  of  dealing  with 
the  intensities  of  sensation  led  indirectly  to  the  estab- 
lishment of  a  law  of  relation  between  stimulus  and  sensa- 
tion which  is  known  from  the  name  of  the  man  who  first 
noticed  the  relation  as  Weber's  law.  This  law  states 
the  relation  that  exists  between  sensation  and  stimulus. 
The  least  noticeable  difference  between  two  stimuli  is 
not  constant  for  all  intensities,  but  varies  with  the  inten- 
sity of  the  stimuli  compared.  Thus  if  one  lifts  an  ounce 
weight,  it  is  found  that  he  can  distinguish  an  addition  of 
one-fortieth  of  an  ounce.  With  a  pound  as  a  standard 
one  must  add  one-fortieth  of  a  pound  before  a  difference 
may  be  noticed.  In  any  sense-department  it  has  been 
found  that  an  addition  to  be  just  noticed  must  be  some 
fraction  of  the  stimulus  present,  rather  than  an  absolute 
amount.  The  fraction  that  must  be  added  is  different 
for  each  sense.  It  varies  from  about  one  one-hundredth 
for  sight  to  about  one-third  or  one-fourth  for  smell. 
Several  different  formulae  have  been  used  to  express  the 
relation.  Perhaps  the  best  known  and  the  simplest  is 
that  sensations  increase  in  arithmetical  ratio,  if  stimuli 


100  ESSENTIALS   OF   PSYCHOLOGY 

increase  in  geometrical  ratio.  The  stimulus  must  always 
be  multiplied  by  four- thirds  ($),  let  us  say,  to  obtain 
the  next  unit  of  sensation. 

The  most  obvious  outcome  of  the  law  in  everyday  life 
is  that  only  relative  differences  can  be  appreciated.  One 
is  aware  of  the  relative  difference  in  brightness  between 
the  black  of  the  print  and  the  white  of  the  page,  but  is 
not  aware  of  the  absolute  change  in  the  brightness  of 
each  between  noon  and  evening.  Were  the  law  to  hold 
absolutely,  the  light  might  fade  and  we  be  unaware  of  it. 
The  fraction  that  can  be  noticed  is  not  absolutely  con- 
stant, however,  but  holds  only  for  the  middle  ranges  of 
intensity.  As  the  light  grows  dim,  the  just  distinguish- 
able differences  must  increase,  until  at  twilight  white 
must  be  more  than  sixty  times  as  bright  as  the  black  of 
the  print  to  be  readily  noticed  as  different  from  it.  Simi- 
larly, as  the  absolute  brightness  is  increased,  the  fraction 
increases  or,  put  the  other  way,  the  relative  sensitivity 
decreases.  Slight  differences  are  not  so  easily  noticed 
in  the  full  glare  of  the  sun  as  in  diffuse  daylight.  One 
cannot  read  ordinary  print  at  night  or  with  ease  in  the 
glare  of  the  noonday  sun. 

Not  only  may  differences  between  intensities  be  too 
slight  to  be  noticed,  but  stimuli  may  be  too  faint  to  give 
rise  to  any  sensation  whatever.  As  one  moves  a  watch 
away  from  the  ear,  the  sound  becomes  fainter  and  fainter 
until  it  finally  disappears.  One  may  touch  a  pressure 
spot  on  the  skin  with  a  hair  so  soft  that  it  gives  no  sensa- 
tion. The  intensity  that  can  be  barely  noticed,  that  first 
gives  rise  to  a  sensation,  is  called  the  liminal  or  threshold 
stimulus.  At  the  other  extreme  it  is  probable  that  a 


SENSATION  1 01 

stimulus  may  be  too  intense  to  be  felt.  Probably,  how- 
ever, intensities  that  do  not  destroy  the  sense-organ 
merely  tend  to  be  lost  in  the  accompanying  pain ;  they  do 
not  actually  disappear.  The  upper  limen  is  of  relatively 
little  importance,  and  there  is  little  known  about  it 
because  of  the  injury  which  work  upon  it  might  do  to  the 
sense-organ. 

EXERCISES 

1 .  Mark  off , an  area  on  the  skin  a  centimetre  square.     Press  upon 
each  point  of  the  area  with  a  pointed  metal  rod  warmed  to  about 
40°  C.     Mark  the  spots  where  warmth  is  felt.     Repeat  with  the 
rod  cooled  by  immersion  in  ice-water.     Mark  the  points  where 
cold  is  felt.     Compare  with  the  warm  spots.     Are  they  the  same  ? 
Stimulate  a  definite  cold  spot  with  a  rod  heated  to  about  55°  C. 
What  stimulus  do  you  receive  ?     Why  ? 

2.  Press  gently  upon  the  different  regions  of  the  area  above  with 
a  pointed  toothpick  or  human  hair.     Mark  the  points  where  press- 
ure is  felt.     Go  over  the  same  area  with  a  sharpened  horsehair 
fastened  by  wax  to  a  handle.     Note  the  points  where  pain  is  felt. 
Compare  with  pressure  and  with  the  temperature  spots.     Can  you 
make  out  any  law  of  arrangement  ? 

3.  Observe  in  a  glass  the  red  openings  of  the  papillae  on  the  end  of 
the  tongue.     Mark  five  papillae  on  a  drawing  of  the  tongue.    With 
a  brush  stimulate  each  papilla  successively  with  a  solution  of  salt, 
sugar,  vinegar,  and  quinine.     Are  all  of  the  spots  sensitive  to  each 
substance?    How  can  you  explain  the  results  by  the  doctrine  of 
specific  energies  ? 

4.  Fatigue  "the  nostril  for  camphor  by  smelling  a  lump  of  the  gum 
until  it  is  no  longer  perceived.     Try  the  nose  for  iodine.     Fatigue 
again  for  camphor  and  try  for  vanilla.     Test  in  the  same  way  for 
rubber,  asafcetida  and  other  substances.     What  do  the  results 
prove  of  the  nature  of  olfactory  qualities  ? 

5.  Draw  the  ear  to  demonstrate  the  relations  of  the  bones  of  the 
middle  ear  to  the  cochlea  and  the  auditory  nerve. 


102          ESSENTIALS  OF  PSYCHOLOGY 

6.  Demonstrate  the  presence  of  overtones  in  a  note  of  the  piano. 
Strike  the  lowest  C  while  the  key  that  gives  the  octave  is  held  down. 
As  the  first  key  is  dropped  you  will  hear  the  octave  still  resounding 
by  sympathetic  action  induced  by  the  first  overtone  of  the  funda- 
mental.    Proceed  in  the  same  way  to  determine  what  other  over- 
tones are  present  in  the  note  first  struck.     How  are  these  overtones 
heard  in  the  ear  ? 

7.  Mix  blue  and  yellow  in  different  combinations  on  a  rotating 
colour-mixer.     If  this  be  not  at  hand,  a  substitute  may  be  prepared 
as  follows  :  Place  a  square  of  yellow  paper  and  a  square  of  blue  paper 
of  the  same  size  upon  a  black  cloth  on  a  table  a  foot  apart.     Hold  a 
pane  of  clear  glass  vertical  midway  between  them  and  look  through 
the  glass  at  one,  and  adjust  the  second  square  so  that  its  reflected 
image  covers  the  first.    When  the  two  colours  are  brought  to  coincide 
the  apparatus  makes  a  simple  colour  mixer.     The  intensities  of  the 
colours  may  be  varied  by  turning  the  glass  plate  about  the  line  of 
contact  with  the  table.     What  colour  does  the  mixture  of  blue  and 
yellow  give  rise  to  when  the  apparatus  is  adjusted  to  give  equal 
amounts  of  each  ?     Try  mixtures  of  other  primary  colours  to  give 
the  list  of  spectral  colours. 

8.  Place  a  bit  of  green  paper  over  a  dot  on  a  sheet  of  grey  paper. 
Look  intently  at  the  green  paper  for  ten  seconds.     Blow  the  green 
bit  away  and  look  for  three  seconds  or  so  at  the  dot.   What  colour  re- 
places the  green  ?    Repeat  with  the  other  colours  and  record  results. 

9.  Place  a  centimetre  square  of  grey  paper  on  a  large  square  of 
red.     Cover,  both  with  tissue  or  other  translucent  paper.     Note 
the  colour  of  the  small  square  as  seen  through  the  tissue  paper. 
What  gives  it  a  colour  ?    Test  on  surfaces  of  other  colours.    What 
is  the  general  law  ? 

10.  Look  steadily  at  a  point  on  a  wall,  preferably  a  grey  wall. 
Have  an  assistant  move  centimetre  squares  of  coloured  paper  away 
from  the  fixation  point.    Note  the  point  where  the  different  colours 
disappear  or  change.     Measure  the  distance  from  the  fixation  point 
in  different  directions.    Compare  the  distances  for  different  colours. 
Can  you  interpret  the  results  by  the  phenomena  of  colour-blind- 
ness mentioned  in  the  text  ? 


SENSATION  103 

11.  Draw  the  eye  showing  the  lens  system  and  its  relation  to  the 
iris,  retina,  and  various  coats.    On  a  larger  scale  draw  a  portion  of 
the  retina  that  shall  indicate  the  nervous  connections  between  the 
rods  and  cones  and  the  fibres  of  the  optic  nerve. 

12.  Bend  the  finger  at  the  second  joint.     Can  you  detect  deeper 
lying  sensations  ?     Can  you  distinguish  them  in  quality  from  the 
pressure  sensations  ?    What  is  the  sense-organ  that  gives  rise  to 
them? 

REFERENCES 

TITCHENER  :  Text-book  of  Psychology,  pp.  59-224. 

ANGELL:  Psychology,  pp.  109-150. 

HOWELL  :  Text-book  of  Physiology,  pp.  264-403. 

MEYERS:  Experimental  Psychology,  pp.  11-122. 

SEASHORE:   Elementary   Experiments  in   Psychology,  chs.   i-iii, 

vii,  viii  (for  further  experiments  and  fuller  description  of  the 

experiments  described  in  the  exercises). 


CHAPTER   V 
SELECTION  AND   CONTROL  —  ATTENTION 

ONE  of  the  most  striking  facts  of  consciousness  is  selec- 
tion or  control.  A  man  is  not  absolutely  under  the  domi- 
nation of  habit,  of  external  stimulation,  or  of  the  habitual 
elements  in  the  thinking  processes,  but  can  decide  for 
himself,  within  limits,  what  he  shall  hear  or  see,  what  he 
shall  think  or  what  he  shall  do.  He  may  admit  faint 
stimuli  to  consciousness  while  stronger  ones  are  acting 
upon  the  sense-organs;  he  may  repress  a  strong  habit 
and  permit  a  weaker  one  to  run  its  course;  or  he  may 
choose  a  faint  memory  when  several  that  are  ordinarily 
more  insistent  are  pressing  for  return.  Evidently,  selec- 
tion is  of  fundamental  importance  in  perception,  in  action, 
and  in  memory.  Since  selection  affects  so  many  different 
processes  and  has  so  many  different  phases,  it  becomes 
necessary  to  distinguish  between  the  questions  that  may 
be  answered  in  the  same  way  everywhere  and  those  that 
must  be  treated  differently  in  each  field.  Three  questions 
must  be  answered  in  connection  with  each  kind  of  selec- 
tion :  (i)  what  is  the  effect  of  selection  upon  the  process 
affected?  (2)  what  determines  the  course  of  selection? 
(3)  what  are  the  concomitants  of  the  selective  activity  ? 
Of  these  the  first  takes  different  forms  hi  each  field; 
the  second  and  third  are  general :  an  answer  in  one  con- 
104 


SELECTION   AND   CONTROL  —  ATTENTION  10$ 

nection  will  hold  with  little  change  for  both  of  the 
others.  The  conditions  of  selection  and  the  means  of 
knowing  that  selection  is  being  made  are  the  same  for 
perception,  for  memory,  and  for  will.  In  this  chapter 
we  shall  discuss  primarily  the  selection  of  sensations 
or  attention,  but  we  shall  also  point  out  the  similarities 
between  the  attention  processes  and  the  control  processes 
in  thought  and  action. 

The  general  effects  of  selection  are  the  same  for  percep- 
tion, for  thought,  and  for  action.  We  read  on  a  railroad 
train  in  spite  of  the  noise  and  other  distractions ;  we  hear 
the  faint  sounds  of  a  conversation  in  a  storm  or  in  a  boiler 
shop  and  are  for  the  moment  not  aware  of  the  din.  When 
studying  attentively,  one  may  be  spoken  to  several  times 
without  being  disturbed.  Similarly,  one  can  continue  a 
train  of  thought  even  when  other  very  pleasant  memories 
suggest  themselves  or  in  the  midst  of  external  disturb- 
ances. A  stimulus  that  has  given  rise  on  different  occa- 
sions to  a  number  of  different  responses  and  might  now 
be  the  means  of  exciting  several  different  movements 
will  arouse  but  one  of  these,  —  that  one  will  be  selected 
from  the  others  that  are  possible.  Each  of  these  selec- 
tions is  of  the  same  kind.  One  process  is  given  free  rein ; 
all  others  are  checked. 

More  frequently  in  attention,  the  processes  not  selected 
are  not  absolutely  excluded  from  consciousness,  but  are 
given  a  subordinate  place.  As  one  attends,  certain  sen- 
sations are  clearly  appreciated ;  the  others  are  less  clear. 
One  of  the  much  discussed  problems  of  attention  concerns 
the  difference  between  the  sensation  that  is  directly 
attended  to  and  the  others  that  constitute  the  background 


106          ESSENTIALS  OF  PSYCHOLOGY 

of  consciousness.  Two  conflicting  theories  have  been 
held :  one,  that  attention  increases  the  intensity  of  the 
sensation,  the  other,  that  the  change  is  peculiar  and  must 
be  given  a  different  name,  clearness.  All  agree  that  the 
effect  of  attention  is  similar  to  increased  intensity.  Both 
make  the  sensation  easier  to  describe,  make  all  judgments 
about  it  more  accurate,  and  give  it  a  more  important 
place  in  consciousness.  But  the  two  effects  must  be 
different  in  some  way  for  one  seldom  mistakes  a  change 
in  attention  for  a  change  in  the  intensity  of  the  stimulus. 
It  is  not  assumed  that  the  tone  of  a  violin  has  increased  in 
intensity  when  its  tones  are  picked  out  from  the  mass  of 
an  orchestra,  nor  is  it  assumed  that  the  tactual  sensations 
grow  weak  when  they  are  not  attended  to.  It  is  certain 
that  attention  and  intensity  are  sufficiently  different  in 
their  effect  upon  consciousness  to  prevent  them  from 
being  mistaken  for  each  other.  It  is  generally  asserted 
that  attention  increases  the  clearness  of  a  mental  state. 
The  state  becomes  clearer,  its  details  are  more  promi- 
nent, it  can  be  more  easily  used  and  understood.  This 
quality  of  clearness  is,  however,  different  from  intensity 
in  spite  of  the  fact  that  both  make  a  mental  state  more 
important. 

Analysis  and  Synthesis.  —  Analysis  and  synthesis  may 
both  be  referred  to  the  effect  of  selecting  different  states. 
In  analysis  some  one  part  of  a  total  process  is  made 
prominent,  and  this  makes  possible  the  recognition  of 
its  constituents.  As  one  listens  to  a  chord  attending  to 
one  of  the  notes,  that  note  becomes  prominent  in  the 
complex.  Analysis  of  the  chord  consists  in  making  each 
of  its  components  prominent  one  after  another.  Syn- 


SELECTION  AND  CONTROL — ATTENTION     107 

thesis  is  also  a  result  of  increasing  the  clearness  of  mental 
states.  It  differs  from  analysis  only  in  that  the  total 
effect  of  the  mass  is  attended  to  rather  than  some  one 
component.  In  the  chord  one  may  attend  to  determine 
the  closeness  of  fusion  of  the  components  or  the  pleasant- 
ness of  the  whole.  This  serves  to  unite  the  elements 
into  a  single  whole.  The  results  of  attention  may  be 
either  to  analyse  or  to  synthesise,  but  in  either  case  the 
primary  effect  is  to  increase  the  prominence  of  part  or 
of  whole.  This  change  in  clearness  with  the  resulting 
analysis  or  synthesis  may  affect  memory  or  thought 
processes  as  well  as  sensations.  One  may  analyse  either 
the  memory  or  the  sensational  elements  from  a  percep- 
tion, or  one  may  turn  from  a  perception  to  study  mental 
imagery,  or  may  attend  to  one  part  after  another  of  an 
idea.  The  effect  upon  ideas  is  the  same  as  upon  sensa- 
tions. In  action,  selection  is  more  likely  to  be  of  wholes 
than  of  parts,  although  on  occasion  one  element  of  a 
complex  act  may  be  emphasised  without  changing  the 
others. 

The  Conditions  of  Attention.  —  Why  one  selects  or 
attends  is  not  so  easy  to  determine.  Usually  the  con- 
ditions are  hidden.  Attention  comes  without  antece- 
dent desire  or  warning.  One  often  finds  one's  self  at- 
tending without  any  preliminary  intention  and  even 
against  one's  will.  When  one  desires  to  attend,  in 
advance  of  attention,  it  is  a  problem  why  one  desires, 
and  this  usually  escapes  notice  even  when  the  question 
is  raised.  Nearly  always  one  is  concerned  to  know  only 
that  one  desires  to  attend  and  does  not  care  to  know 
why.  Indirect  methods,  however,  have  thrown  con- 


IOS          ESSENTIALS  OF  PSYCHOLOGY 

siderable  light  upon  the  conditions  of  attention.  These 
methods  consist  in  studying  the  circumstances  in  the 
individual  and  the  outside  world  that  precede  attention, 
and  in  generalising  the  results  of  the  observation  in  laws. 
In  the  light  of  these  observations  two  sets  of  conditions 
may  be  distinguished,  the  subjective  and  the  objective. 
The  one  is  a  series  of  circumstances  in  the  outside  world 
that  precedes  attention,  the  other  the  earlier  experiences 
of  the  individual.  These  conditions  may  be  first  deter- 
mined for  attention  to  external  stimuli,  although  the 
results  hold  for  all  selection. 

Objective  Conditions  of  Attention.  —  The  circum- 
stances in  the  outer  world  that  favour  the  entrance  of  a 
sensation  are  to  be  found  in  the  amount  of  energy  that 
the  stimulus  expends  upon  the  sense-organ.  The  amount 
of  energy  expended  may  be  due  to  the  intensity  of  the 
stimulus,  to  its  duration,  or  to  the  area  of  the  sense-organ 
that  it  affects.  An  intense  sound  such  as  an  explosion, 
a  bright  light,  a  strong  odour,  will  force  themselves  upon 
attention,  however  much  it  may  be  desired  to  keep  it 
fixed  upon  something  else.  Similarly  a  large  object  will 
be  seen  where  a  small  one  might  escape  notice.  Up  to 
a  certain  point,  too,  the  greater  the  duration  of  a  stimu- 
lus, the  more  likely  it  is  to  enter  consciousness.  Beyond 
that,  greater  duration  leads  to  neglect;  one  attends  and 
passes  on  to  something  else,  and  the  stimulus  is  no 
longer  appreciated.  This  is  but  another  way  of  stating 
that  change  is  more  important  than  absolute  intensity 
or  extent  in  determining  the  course  of  attention.  One 
notices  a  whistle  of  changing  pitch  or  intensity  where 
a  constant  one  would  escape  notice.  One  even  appre- 


SELECTION    AND    CONTROL — ATTENTION  1 09 

ciates  the  ticking  of  a  watch  as  it  stops,  although  the 
preceding  continuous  ticking  has  not  been  noticed  at  all. 
Similarly,  objects  that  move  towards  or  away  from  us 
are  noticed,  although  the  same  objects  would  escape 
notice  if  stationary,  and  our  only  way  of  knowing  that 
they  move  away  or  approach  is  from  the  changing  size. 
Change,  whether  in  size  or  intensity,  whether  it  be  in- 
crease or  decrease,  will  attract  attention.  These  char- 
acteristics of  the  outside  world  that  play  a  part  in  de- 
termining whether  a  sensation  shall  be  noticed,  may  be 
said  to  be  opposed  to  attention.  They  express,  not  the 
selective  activity  of  consciousness,  but  the  forces  in  the 
outside  world  that  oppose  voluntary  selection.  If  they 
alone  acted,  man  would  not  be  the  controller  of  his  own 
consciousness,  but  a  plaything  of  external  forces.  It  is 
usual  to  extend  the  meaning  of  the  term  attention  to 
cover  the  factors  that  explain  the  entrance  of  sensa- 
tions, and  in  any  case  one  cannot  understand  the  sub- 
jective factors  without  a  knowledge  of  these  objective 
conditions,  whether  one  calls  them  conditions  of  atten- 
tion or  not.  One  might  add  in  this  connection,  in  an- 
ticipation of  the  later  discussions,  that  there  are  similar 
objective  conditions  that  oppose  subjective  control,  both 
in  memory  and  in  action.  In  both,  these  are  found  in 
the  closeness  of  connection  between  sensation  or  idea 
and  other  ideas  or  movements.  The  development  of  the 
laws  must  be  left  to  the  later  chapters. 

The  Subjective  Conditions  of  Attention.  —  What  give 
the  individual  spontaneity  and  self-expression  in  the 
selection  of  sensations  are  the  subjective  conditions. 
They  reflect  the  earlier  life  of  the  individual  in  very  much 


HO  ESSENTIALS    OF   PSYCHOLOGY 

the  same  way  that  the  objective  conditions  reflect  the 
outer  world  at  the  moment.  It  is  possible  to  enumerate 
five  factors  of  greater  or  less  generality  that  are  accepted 
as  playing  a  part  in  determining  the  nature  of  attention. 
Enumerated  in  the  order  of  nearness  in  time  to  the  par- 
ticular act  of  attending,  these  are:  (i)  the  idea  in  mind, 
(2)  the  purpose  or  attitude  at  the  moment,  (3)  the  earlier 
education,  (4)  duty  (as  the  expression  of  social  or  indi- 
vidual ideals),  and  (5)  heredity.  The  first  can  be  seen 
either  in  the  influence  of  an  immediately  preceding  sen- 
sation or  of  an  immediately  preceding  idea.  If  one  has 
heard  or  seen  or  is  thinking  of  some  object  and  that 
object  presents  itself,  it  will  be  noticed  where  otherwise  it 
might  escape  attention.  In  listening  for  an  overtone  it 
is  easier  to  hear  it  if  one  has  heard  the  same  tone  at  full 
strength  just  before.  Similarly,  in  listening  to  an  orches- 
tra if  one  will  picture  to  one's  self  the  tones  of  a  violin 
or  will  look  at  the  violin,  one  will  be  certain  to  catch 
the  tones  of  that  instrument  when  otherwise  one  would 
miss  them.  When  looking  for  an  article  with  the  picture 
definitely  in  mind,  one  will  see  it  at  once.  When  one  is 
looking  through  a  glass  for  a  bird  in  a  tree,  one  will  con- 
tinue to  see  it  when  it  has  once  been  seen,  although  one 
may  have  looked  for  it  a  long  time  before  it  was  first 
discovered. 

The  second  of  the  subjective  conditions  of  attention 
shows  three  degrees  of  consciousness  of  its  action.  Each 
is  an  expression  of  a  conscious  state  or  mental  attitude 
and  is  a  little  more  general  than  the  idea  or  sensation 
that  is  prominent  at  the  moment. '  The  most  usual  and 
most  definite  way  of  arousing  the  attitude  is  to  ask  a 


SELECTION   AND    CONTROL — ATTENTION  III 

question.  This  may  be  illustrated  by  a  simple  experi- 
ment. Cut  a  number  of  bits  of  paper  qf  different 
shapes  and  colours.  Cover  them  with  a  piece  of  card- 
board and  expose  them  for  an  instant  as  you  ask,  'What 
colours  do  you  see  ?  '  After  exposure  the  observer  can 
tell  pretty  accurately  what  colours  were  shown.  If  then 
you  ask  him  what  the  forms  were  or  how  many  bits 
were  shown,  it  will  be  found  that  he  can  give  no  correct 
answer.  One  sees  what  corresponds  to  the  question ; 
all  else  is  excluded  from  consciousness.  Sometimes  the 
question  arises  spontaneously  or  is  suggested  by  a  sen- 
sation You  wonder  if  it  is  raining,  and  as  you  look 
out  of  the  "window  with  this  question  in  mind,  you  notice 
a  drizzle  or  see  spots  upon  the  roof  that  would  other- 
wise have  escaped  observation.  Very  many  observa- 
tions grow  in  this  way  out  of  specific  questions,  and  it  is 
surprising  to  note  how  certain  the  question  is  to  bring 
to  mind  any  object  that  may  contain  the  answer  to,  or 
correspond  to,  the  question,  and  how  little  one  sees  that 
does  not  correspond.  Most  people  cannot  say  whether 
the  four  on  the  watch  is  IIII  or  IV,  because  they  look 
for  the  time,  not  the  characters.  Next  in  order  of 
conscious  anticipation  is  the  purpose.  Usually  one  has 
some  definite  purpose  in  observation  as  in  action,  and 
this  serves  to  control  attention  even  when  there  is  no 
definite  question  in  mind.  In  a  laboratory  one  may  be 
seeking  for  the  solution  of  some  problem  with  no  definite 
question  formulated.  Under  those  circumstances  he  is 
very  likely  to  notice  anything  that  harmonises  with  his 
purpose.  Similarly  one  notices  animal  life  in  the  field 
of  a  microscope  more  easily  in  the  zoological  laboratory, 


112  ESSENTIALS   OF    PSYCHOLOGY 

and  plant  structures  more  easily  in  the  botanical  labora- 
tory. The  purpose  is  not  very  insistent  in  these  cases 
but  is  none  the  less  operative.  In  everyday  life  what  is 
appreciated  corresponds  very  closely  to  the  purpose, 
whether  that  purpose  be  serious  and  permanent  or  trivial 
and  transitory.  On  a  hunting  trip  one  is  set  for  the  per- 
ception of  game,  as  in  a  class  room  one  is  set  to  under- 
stand a  lecture  or  hear  a  question.  This  '  set '  constitutes 
the  purpose,  and  is  effective  even  when  not  kept  in  mind. 
One  often  has  still  less  definitely  conscious  '  sets.'  In 
these  one  is  not  aware  of  a  purpose  and  has  no  definite 
question.  The  bias  arises  from  some  previous  experi- 
ence and  is  not  preceded  by  a  desire  to  see  one  thing  or 
group  of  things  rather  than  another.  Nevertheless  any 
object  that  corresponds  to  the  attitude  will  be  noticed 
at  the  expense  of  other  objects.  After  one  has  detected 
escaping  gas,  other  odours  will  be  more  likely  than  usual  to 
be  noticed,  even  after  all  thought  of  detecting  an  odour  has 
vanished.  All  three  of  these  factors  serve  to  quicken 
attention  for  one  group  of  things  rather  than  for  another, 
and  together  they  constitute  the  most  important  con- 
dition of  attention.  What  does  not  correspond  to  the 
attitude,  purpose,  or  question  of  the  moment  is  not 
admitted  to  consciousness,  and  all  that  does  correspond 
to  it  will  be  noticed,  no  matter  how  unfavourable  the  cir- 
cumstances in  other  respects.  Practically  the  only 
difference  in  the  three  sorts  of  attitudes  is  to  be  found 
in  the  degree  of  anticipation  of  the  object  attended  to. 
The  question  very  definitely  foreshadows  the  object  of 
attention ;  the  purpose  gives  only  a  general  idea  of  the 
class  of  objects  to  be  expected ;  while  the  attitude  is  not 


SELECTION    AND    CONTROL — ATTENTION  113 

at  all  conscious  and  gives  no  expectation.  The  attitudes 
change  from  hour  to  hour,  and  even  from  moment  to 
moment.  They  are  practically  the  only  occasions  for 
the  shifting  of  attention. 

Education  as  a  Condition  of  Attention.  —  The  influence 
of  the  earlier  life  in  determining  the  general  character  of 
attention  is  as  marked  as  the  influence  of  the  attitude 
in  the  changes  of  its  temporary  character.  Two  influ- 
ences of  education  may  be  distinguished.  First  it  makes 
attention  of  certain  forms  more  effective.  The  skill  of 
tea  and  wine  tasters,  the  keenness  of  the  savage  for 
following  a  trail,  are  due,  not  to  any  improvement  in  the 
sense-organ  through  practice,  but  to  training  hi  atten- 
tion. In  every  sense  department  and  in  every  sort  of 
observation  one  comes  with  practice  to  appreciate  dif- 
ferences that  at  first  cannot  be  detected.  One  important 
result  of  any  sort  of  education  is  the  increased  capacity 
for  observation.  A  second  effect  of  education  upon 
attention  is  the  more  usual  one  of  determining  the 
stimulus  that  shall  be  appreciated.  What  is  seen  or 
heard  is  usually  an  indication  of  the  character  of  earlier 
experiences.  If  a  man  enters  a  strange  room,  the  first 
object  noticed  is  one  that  earlier  education  has  prepared 
him  to  see.  A  fisherman  will  notice  the  rod  on  the  wall, 
the  athlete  will  notice  the  foil  or  the  lacrosse  stick,  the 
scholar  will  notice  the  books,  the  artisan  the  implements 
of  his  trade.  It  is  possible  to  tell  fairly  closely  a  man's 
occupation  or  training  by  studying  the  objects  that  he 
observes  and  the  order  in  which  they  present  themselves. 
Even  more  generally  one  will  hear  his  own  name  spoken 
in  conversation  when  nothing  else  is  heard.  Sometimes 


114  ESSENTIALS   OF   PSYCHOLOGY 

education  acts  indirectly  by  preparing  questions  and 
purposes;  often  education  acts  directly  —  one  is  not 
aware  of  any  purpose.  In  brief,  education  gives  capacity 
for  discrimination  and  also  determines  the  order  in  which' 
presented  objects  shall  enter  consciousness,  and  whether 
they  shall  enter  at  all. 

Social  Determinants  of  Attention.  —  One  effect  of 
education  upon  attention  is  important  enough  for  sepa- 
rate mention.  This  is  the  effect  of  social  training  which 
serves  to  hold  attention  to  the  momentarily  unpleasant 
for  the  attainment  of  future  pleasure.  One  is  con- 
stantly being  taught  that  certain  things  must  be  attended 
to  in  spite  of  the  fact  that  others  are  more  in  harmony 
with  the  momentary  mood.  It  is  of  course  not  possible 
to  analyse,  in  their  completeness,  the  forces  that  make 
for  this  sort  of  attention,  but  so  far  as  they  can  be  ana- 
lysed they  may  be  related  to  social  influences  and  may 
be  brought  together  under  the  term  social  pressure. 
One  ordinarily  works  for  the  object  at  present  less 
pleasant  to  gain  some  greater  remote  good.  The  value 
of  the  remote  good  is  learned  from  and  usually  enforced 
by  society,  and  enforced  as  a  duty,  not  as  a  good.  The 
impulse  to  work  for  it  is  given  through  ideals,  and  the 
ideals  can  be  traced  to  the  society  of  the  individual. 
The  boy  of  to-day  seeks  to  avoid  manual  labour  and  to 
enter  the  professions,  even  when  they  are  relatively  un- 
remunerative,  because  of  the  small  esteem  in  which 
working  with  the  hands  is  held  by  society.  Each  ideal 
of  the  kind  demands  for  its  attainment  holding  attention 
for  a  long  time  to  matter  that  is  not  pleasant.  When 
you  turn  from  reading  a  novel  to  this  chapter,  you  are 


SELECTION   AND    CONTROL — ATTENTION  115 

governed  by  social  pressure.  First  the  pressure  exerted 
by  teacher  and  class  to  stand  well,  then  the  desire  to 
attain  the  end  for  which  this  knowledge  is  a  prepara- 
tion, and  finally  that  end  is  itself  desirable  because  of 
the  social  approval  that  it  receives.  The  punishment  of 
failing  to  attend  is  social  contempt ;  the  reward  of  per- 
sistent attention  is  social  approval.  Society  sets  the 
end,  social  pressure  compels  one  to  attend  for  its  attain- 
ment. The  attention  that  comes  from  social  pressure  is 
distinguished  from  the  other  forms  of  attention  due  to 
education  in  that  the  end  and  the  process  are  unpleasant, 
and  attending  seems  the  result  of  effort  in  the  one,  while 
in  the  other  the  end  and  process  are  pleasant  and  the 
process  is  interesting. 

Heredity  and  Attention.  —  In  addition  to  the  tenden- 
cies that  develop  in  the  life  of  the  individual,  some  must 
be  referred  to  heredity.  Under  this  head  come  both  the 
most  general  characteristics  of  mankind  and  some  of  the 
family  and  individual  peculiarities.  Under  the  first 
head  falls  the  fact  that  all  are  attracted  by  movement 
and  by  individuals  of  the  opposite  sex,  and  that  love 
stories  and  stories  of  fighting  universally  hold  us.  Under 
the  second  fall  the  differences  in  taste  that  individuals 
show.  Liking  for  music  or  art  goes  back  in  part  to  a 
tendency  to  observe  certain  stimuli  rather  than  others. 
Many  similar  characteristics  and  capacities  must  be  ex- 
plained in  large  part  by  innate  differences  in  attention. 
It  is  still  impossible  to  say  how  far  any  particular  act  of 
attention  is  due  to  an  hereditary  influence  and  how  far 
to  education  and  other  acquired  tendencies.  Certain  it 
is,  however,  that  each  plays  an  important  part.  The 
more  fundamental  ways  of  attending  are  hereditary. 


Il6          ESSENTIALS  OF  PSYCHOLOGY 

The  Nervous  Basis  of  Attention.  —  In  harmony  with 
our  preliminary  statement  that  all  mental  action  has  a 
corresponding  activity  in  the  cortical  cells,  it  is  neces- 
sary to  relate  the  conditions  of  attention  to  nervous 
processes.  The  nervous  basis  of  attention  is  undoubtedly 
the  selective  preparation  of  certain  cortical  cells  that 
makes  them  easier  to  arouse  than  others.  This  prepa- 
ration is  a  state  of  partial  activity  that  needs  but  to  be 
increased  by  the  stimulus  to  give  full  consciousness.  In 
consequence  a  stimulus  too  weak  to  affect  cells  not  thus 
prepared  will  arouse  these  to  full  activity.  Each  of  the 
conditions  discussed  above  may  be  traced  to  some  prepa- 
ration of  this  sort.  The  influence  of  the  immediately 
preceding  stimulus  is  to  leave  the  cells  it  excites  in  a 
state  of  partial  activity ;  they  are  still  quivering  from  the 
earlier  stimulation,  and  so  respond  easily  to  the  new 
stimulus.  The  influence  of  the  question  or  purpose  is  to 
arouse  in  some  slight  degree  a  whole  group  of  connected 
cells.  When  a  question  is  asked,  the  nervous  impulse 
spreads  from  the  cells  excited  by  the  question  to  others 
that  have  previously  been  excited  in  the  same  connec- 
tion. An  object  appealing  to  any  one  of  these  cells 
will  find  entrance  to  consciousness  made  easy  for  it. 
Part  of  the  work  of  exciting  the  cells  has  already  been 
done.  The  influence  of  education  is,  first,  to  connect  the 
nerve-cells  into  large  groups,  and  so  to  prepare  for  ques~' 
tions  and  purposes,  and  secondly,  to  make  possible  the 
spread  of  preparation  from  element  to  element,  and  thus 
to  determine  the  course  of  the  spread  of  preparation. 
It  probably  also  makes  certain  paths  permanently  more 
permeable,  and  so  more  open  to  excitation  than  they 


SELECTION  AND  CONTROL  —  ATTENTION     117 

were  in  advance  of  training.  The  hereditary  bias  has  a 
similar  explanation,  except  that  the  selective  perme- 
ability is  present  in  advance  of  training.  Preliminary 
preparation  in  the  nervous  system  is  correlated  with 
selection  of  sensations  in  consciousness,  and  each  of  the 
conditions  of  selection  corresponds  on  the  nervous  side 
to  an  occasion  for  preparation. 

Interest  and  Effort  in  Attention.  —  The  conditions  of 
attention  can  be  reduced  to  certain  peculiarities  in  the 
outside  world  and  to  different  events  in  the  life  of  the 
individual.  But  if  one  should  ask  the  average  non- 
scientific  individual  why  he  attends,  he  would  answer 
in  practically  every  case  that  he  attended  because  he 
was  interested  or  because  he  forced  himself.  If  we 
examine  our  own  consciousness,  it  is  evident  that  atten- 
tion from  interest  and  attention  from  effort  are  natural 
divisions.  It  is  desirable  to  refer  this  popular  explana- 
tion and  classification  to  the  conditions  already  dis- 
cussed. A  list  of  the  things  that  are  called  interesting 
includes  those  that  are  attended  to  naturally  and  uni- 
versally, such  as  stories  of  conflict.  Attention  to  these 
we  have  seen  to  be  due  to  heredity,  to  education,  or  to 
passing  attitude  or  purpose.  Some  interests  are  general 
and  innate,  some  are  acquired  by  education,  and  some 
are  temporary  and  seem  to  come  and  go  without  cause. 
To  say  that  attention  is  due  to  interest  is  merely  to  say 
that  it  is  due  to  some  one  of  the  subjective  conditions 
other  than  social  pressure. 

Attention  from  these  conditions  is  pleasant  and  spon- 
taneous. It  has  sometimes  been  called  non-voluntary 
attention.  The  attention  that  is  said  to  be  due  to  effort 


Il8  ESSENTIALS   OF   PSYCHOLOGY 

falls  almost  universally  under  the  socially  conditioned. 
When  one  is  said  to  strive  to  attend,  the  incentive  is 
ordinarily  some  ideal  of  social  origin.  The  real  occasion 
for  attending  is  the  social  approval  that  is  expected  or 
the  blame  that  is  feared  if  one  fails  to  attend.  The  social 
incentive  is  generally  given  the  name  duty.  This  sort 
of  attention  is  also  marked  off  from  the  others  by  the 
fact  that  it  is  usually  accompanied  by  diffuse  contrac- 
tions in  different  parts  of  the  body  that  give  sensations 
of  strain.  These  constitute  the  feeling  of  effort.  Atten- 
tion that  springs  from  ideals  of  social  origin,  and  is 
accompanied  by  effort,  is  called  voluntary  attention. 
Attention  conditioned  by  the  nature  of  the  stimuli  from 
the  external  world  completes  the  list.  This  is  called  in- 
voluntary attention,  since  it  may  be  opposed  to  the  pur- 
pose and  to  the  dominant  ideals  of  the  moment.  It  is 
always  effortless,  but  may  or  may  not  be  interesting. 
To  exclude  these  stimuli  is  the  usual  object  of  effort. 
We  may  say  that  there  are  three  sorts  of  attention: 
voluntary,  non-voluntary,  and  involuntary.  Voluntary 
attention  is  conditioned  by  social  pressure  and  is  accom- 
panied by  effort ;  non-voluntary  attention  is  conditioned 
by  the  idea  in  mind,  the  mental  attitude  of  the  moment, 
education,  or  heredity, and  is  accompanied  by  interest; 
involuntary  attention  is  conditioned  by  the  character  of 
the  stimuli  that  are  presented,  and  either  is  accompanied 
by  interest  or  is  the  distraction  that  gives  occasion  for 
effort.  The  different  forms  cannot  always  be  distin- 
guished, but  they  serve  the  practical  purposes  of  classifi- 
cation. 
The  Motor  Phenomena  of  Attention.  —  One  of  the 


SELECTION   AND    CONTROL  —  ATTENTION  IIQ 

most  striking  characteristics  of  the  attentive  conscious- 
ness is  the  movements  that  accompany  it.  They  serve 
as  the  only  sign  of  attention  to  the  onlooker,  and  are 
prominent  in  the  experience  of  the  individual  attending. 
As  one  attends,  the  various  sense-organs  are  adjusted  to 
receive  the  impression  most  effectively.  When  one 
attends  to  an  object  in  the  field  of  vision,  the  eyes  spon- 
taneously turn  toward  it,tthe  two  eyes  converge  that  it 
may  be  seen  with  the  fovea  in  each  eye,  and  the  lens  is 
adjusted  to  give  the  clearest  possible  image.  The  turn- 
ing and  converging  of  the  eyes  can  be  seen  by  the  ob- 
server. One  knows  when  talking  to  a  person  whether 
one  is  being  looked  at  or  whether  the  gaze  is  directed 
beyond.  This  is  the  most  common  indication  of  the 
nature  of  the  thing  attended  to.  Not  only  is  there  a 
characteristic  position  of  the  eyes  for  attention  in  the 
field  of  vision,  but  for  hearing  also  and  even  for  touch 
and  taste.  Usually  attention  with  the  other  senses  is 
followed  by  visual  attention  to  the  same  object.  When 
one  hears  a  sound,  one  turns  the  eyes  toward  it,  and 
when  touched,  one  looks  to  see  what  has  touched  the 
skin.  There  are  definite  adjustments  of  the  other  senses 
to  give  the  best  condition  for  observation.  In  addition 
to  the  adjustment  of  the  sense-organs  that  are  essential 
to  perception,  many  more  general  muscular  contractions 
accompany  attending.  One  of  the  most  important  is  the 
inhibition  of  all  movement.  When  listening,  one  checks 
all  movement ;  even  those  that  have  started  are  stopped 
in  mid  course.  Any  sort  of  strong  attention  causes  an 
unintentional  cessation  of  activity.  At  the  same  time 
the  breath  is  held  momentarily,  the  heart  beats  faster, 


120  ESSENTIALS   OF   PSYCHOLOGY 

and  other  changes  in  circulation  may  be  noticed.  Quite 
as  noticeable  and  more  important  from  the  conscious 
side  are  numerous  general  contractions  in  voluntary 
muscles.  In  any  attending  the  muscles  everywhere  are 
slightly  tense.  In  marked  degrees  of  voluntary  atten- 
tion the  brow  is  wrinkled,  the  muscles  of  the  jaws  are  set, 
and  the  fists  may  be  clenched.  All  of  these  are  to  the 
observer  signs  of  attention,  and  at  the  same  time  they 
indicate  to  the  man  who  attends  that  he  is  attending. 
The  diffuse  contractions  give  rise  to  strain  sensations 
which  constitute  the  feeling  of  effort  in  voluntary  atten- 
tion. The  motor  processes  serve  to  adjust  the  sense- 
organs  to  the  most  adequate  reception  of  stimuli,  — • 
holding  the  breath  and  inhibiting  general  movements 
prevent  the  interference  of  distracting  sensations,  while 
the  circulation  is  adapted  to  the  increased  demands  of 
the  organism.  On  the  other  side  they  indicate  to  the 
observer  that  the  man  is  attending,  and  to  himself  they 
give  some  idea  of  the  degree  of  attention  or  at  least  of 
the  amount  of  conflict  in  attention. 

Much  controversy  has  arisen  in  the  last  few  years  as 
to  whether  attention  or  movement  is  primary.  One 
theory  is  that  attention  is  due  to  the  motor  response; 
the  other  that  attention  is  first  and  the  response  a  mere 
accompaniment  or  result.  The  truth  seems  to  lie 
between  them.  The  essential  fact  in  attention  is  the 
selective  preparation.  Movements  of  accommodation 
and  clearness  of  conscious  states  are  both  results  of  this 
preparation.  The  preparation,  as  has  been  seen,  is  the 
outcome  of  the  preceding  activities  of  the  individual, 
near  and  remote,  and  of  the  effects  that  these  activities 


SELECTION  AND  CONTROL — ATTENTION      121 

have  had  upon  the  nervous  organism.  The  effect  of  this 
preparation  as  expressed  in  the  attitude  toward  any 
stimulus  is  what  we  call  attention.  As  seen  by  the  in- 
dividual, this  is  marked  by  selection  of  stimuli  and  by 
clearness  of  certain  conscious  states.  As  seen  by  an- 
other, attention  is  a  series  of  movements,  a  visual  fixa- 
tion, a  bodily  attitude,  or  general  strain.  Of  the  effects 
of  the  preparation,  we  can  never  be  sure  whether  clear- 
ness or  movement  comes  first.  In  many  cases  it  can  be 
observed  that  the  stimulus  presents  itself  in  some  vague 
way  and  the  sense-organs  gradually  adjust  themselves 
to  give  greater  definiteness  of  impression.  This  is  the 
usual  order  in  involuntary  attention.  When  the  stimu- 
lus is  expected,  the  sense-organs  are  prepared  in  advance. 
In  that  case  preparation  is  usually  determined  by  some 
memory  process  which  precedes  and  initiates  movement. 
This  is  true  of  voluntary  and  of  certain  forms  of  non- 
voluntary  attention.  Attention  means,  then,  neither  the 
clearness  of  consciousness  nor  the  movements  that  ac- 
company the  clearing  up  of  a  conscious  state,  but  funda- 
mentally the  condition  of  preparedness  of  the  individual 
and  the  organism  that  gives  rise  at  once  to  the  change 
in  consciousness  and  to  the  movements.  This  prepared- 
ness makes  for  selection,  not  merely  of  sensations,  but 
of  ideas  and  of  movements.  These  have  the  same  con- 
ditions and  the  same  accompanying  states  of  effort  and 
interest.  One  is  interested  in  mental  states  and  actions 
as  one  is  interested  in  objects,  and  one  feels  effort  in 
holding  to  a  train  of  thought  or  in  selecting  a  course  of 
action  as  in  carrying  out  a  difficult  bit  of  reading  or 
observation.  The  same  characteristics  that  are  promi- 


122          ESSENTIALS  OF  PSYCHOLOGY 

nent  in  attention  are  prominent  in  the  selection  of 
thought  and  action.  The  fundamental  phase  of  atten- 
tion is  the  preparedness  that  determines  selection.  It 
is  the  same  in  essence  as  the  factors  that  must  be  dis- 
cussed later  in  connection  with  thinking  and  action. 
This,  not  any  conscious  change  in  sensation  or  move- 
ment, is  the  thing  to  be  emphasised  in  attention.  This 
preparedness  is  not,  however,  itself  conscious.  One  does 
not  know  that  one  is  likely  to  see  one  thing  rather  than 
another  until  he  sees  it,  and  one  does  not  know  that 
certain  movements  of  accommodation  are  coming  until 
they  are  made.  The  only  sign  of  the  change  that  has 
been  wrought  by  earlier  activities  is  their  effect  in 
modifying  selection  and  in  inducing  the  accompanying 
actions. 

The  Duration  of  Attention.  —  Two  practical  questions 
arise  with  reference  to  attention.  The  first  is,  how  long 
any  single  stimulus  may  occupy  the  dominant  place, 
the  second,  how  many  things  may  be  attended  to  at 
once.  To  the  question  how  long  one  may  attend,  various 
answers  have  been  given.  The  ordinary  opinion  is  that 
one  may  attend  indefinitely.  One  seems  to  pay  atten- 
tion to  a  book  that  one  is  reading  for  hours  at  a  stretch, 
and  one  listens  to  a  lecture  for  an  hour  with  slight  dis- 
traction. In  all  such  cases,  however,  the  material  is  con- 
stantly changing,  one  is  not  attending  to  the  same  stimu- 
lus, nor  to  the  same  sensation  during  the  whole  period. 
If  one  attends  to  any  faint  stimulus,  the  ticking  of  a 
watch  or  a  faint  grey  ring  on  a  revolving  disk,  it  will  be 
seen  that  one  does  not  hear  the  sound  nor  see  the  ring 
all  the  time.  It  will  be  seen  for  a  second  or  two,  will 


SELECTION   AND    CONTROL — ATTENTION  123 

vanish  for  four  or  five  seconds,  and  -then  appear  again. 
The  total  length  of  the  cycles  will  be  about  six  to  ten 
seconds.  These  alternations  are  often  called  attention 
waves.  More  recently  they  have  been  referred  to  some 
periodical  change  in  the  sense-organ  or  in  the  nervous 
system,  and  one  must  find  some  other  answer  to  the 
question  how  long  one  may  attend.  While  watching  the 
faint  ring  to  see  when  it  comes  and  goes,  one  is  aware 
of  a  constant  shifting  of  attention.  One  drifts  away 
from  the  ring  to  wonder  whether  one  is  attending  or  is 
attracted  by  some  extraneous  matter  or  thing,  and  often 
the  change  in  the  sensation  comes  while  thus  distracted. 
A  record  that  has  been  made  recently  of  the  maximum 
time  that  attention  can  be  held  to  any  single  stimulus 
indicates  that  the  pulsations  are  very  short  indeed. 
If  one  attempts  to  keep  attention  fixed  upon  a  single 
point  in  a  picture,  it  will  be  found  that  at  least  once  a 
second  something  about  the  point  will  come  in  to  crowd 
it  out  of  consciousness.  If  the  stimulus  be  absolutely 
simple  and  one  is  careful  to  record  each  appearance  of 
something  else,  it  seems  that  one  can  hold  attention 
strictly  to  a  single  thing  for  less  than  a  second.  When 
in  the  popular  sense  attention  is  given  to  a  thing  for  an 
hour  at  a  time,  attention  is  constantly  shifting  from  part 
to  part,  or  is  turning  to  other  objects  or  thoughts  for 
longer  or  shorter  periods.  Attention  for  more  than  a 
second  or  so  to  absolutely  the  same  stimulus  is  either 
impossible  or  results  in  the  pathological  condition  of 
hypnotism. 

The  Range  of  Attention.  —  The  question  of  how  many 
things  may  be  attended  to  at  once  has  also  been  variously 


124  ESSENTIALS   OF   PSYCHOLOGY 

answered  at  different  periods  in  the  history  of  psy- 
chology. The  first,  on  purely  a  priori  grounds,  was  that 
a  unitary  mind  could  have  not  more  than  one  conscious 
process  at  one  time.  More  recently  experiments  dem- 
onstrated that  if  a  number  of  objects  were  shown  for 
one-fifth  of  a  second  or  less,  four  or  five  objects  might  be 
seen.  More  recently  still,  however,  careful  observation 
of  the  process  of  determining  the  number  of  objects 
shows  that  even  with  short  exposures  the  objects  are 
not  attended  to  at  once,  but  are  impressed  upon  con- 
sciousness and  persist  for  a  time  in  the  memory  after- 
image, where  they  may  be  attended  to  separately  and 
counted.  It  is  as  if  one  took  an  instantaneous  photo- 
graph of  a  group  of  objects  and  counted  them  on  the 
film  after  development.  The  memory  after-image  per- 
sists only  a  second  or  two,  however,  and  the  number  of 
objects  that  may  be  seen  with  a  short  exposure  depends 
upon  the  number  that  can  be  attended  to  and  counted 
before  the  image  disappears.  It  seems  probable  from 
all  the  experiments  that  only  a  single  object  may  be 
attended  to  at  once. 

Very  much  the  same  conclusion  has  been  reached 
about  the  related  problem  of  the  number  of  things  that 
may  be  done  at  once.  Often  two  or  more  operations  are 
apparently  carried  on  at  the  same  time.  Careful  in- 
vestigation has  shown  that  two  things  can  be  done  at 
once  only  if  one  has  become  so  habitual  as  to  require 
no  attention.  One  may  easily  carry  on  a  conversation 
while  walking,  but  in  this  case  walking  has  become  so 
automatic  that  it  requires  no  conscious  guidance.  Should 
the  way  become  very  rough,  conversation  will  cease  at 


SELECTION   AND    CONTROL  —  ATTENTION  125 

once  or  will  suffer  long  and  frequent  interruptions.  Ex- 
periments have  been  made  to  show  that  one  can  read 
a  selection  and  add  a  series  of  figures  at  the  same  time 
more  quickly  than  one  could  do  both  in  succession,  but 
if  either  task  is  difficult  enough  to  require  full  attention, 
the  two  will  take  more  time  when  carried  on  together 
than  when  done  successively.  When  easy  and  familiar, 
one  task  will  be  carried  on  automatically  while  attention 
is  given  to  the  other,  but  when  both  require  full  atten- 
tion, only  one  at  a  time  can  be  carried  on  to  advantage. 
Attention  and  Inattention.  —  A  natural  question  arises 
as  to  what  the  opposite  of  attention  may  be,  or  whether 
there  is  ever  a  time  when  one  does  not  attend.  Com- 
plete inattention  is  noticed  only  during  sleep  or  periods 
of  unconsciousness.  Even  in  sleep  there  is  apparently 
some  selective  adaptation  to  stimuli.  A  sleeping  man 
will  be  aroused  by  his  name  even  if  spoken  in  a  tone 
too  low  to  arouse  him  if  heard  in  uninteresting  conversa- 
tion. Even  in  profound  slumber  a  mother  is  '  set '  for 
the  movements  of  her  child,  the  nurse  for  the  patient. 
In  the  insane,  too,  attention  is  present  although  in  a 
reduced  or  distorted  form.  The  so-called  states  of  in- 
attention of  the  normal  man  are  really  states  of  atten- 
tion, but  of  attention  to  something  at  the  moment  un- 
desired.  They  divide  into  two  forms,  —  scattered  or 
diffuse  attention,  and  absent-mindedness.  In  the  one, 
attention  is  constantly  shifting  to  a  new  object,  and  no 
one  is  kept  before  consciousness  long  enough  to  be  fully 
appreciated.  In  the  other,  attention  is  so  absorbed  in 
some  one  thing  or  course  of  thought  that  other  sensa- 
tions have  little  chance  to  enter.  The  first  form  is  more 


I26  ESSENTIALS   OF   PSYCHOLOGY 

frequent  in  childhood  and  in  certain  pathological  states, 
the  other  is  more  usual  in  maturity  and  is  frequently 
found  in  men  of  more  than  usual  training  and  ability. 
Both  forms  of  inattention  are  desirable  if  not  in  excess ; 
in  fact  they  are  extremes  of  the  two  desirable  charac- 
teristics of  attention.  Attention  is  most  effective  when 
all  objects  that  are  useful  are  attended  to,  and  attention 
is  kept  upon  them  long  enough  to  appreciate  them  fully. 
Dispersed  attention  insures  entrance  of  all  important 
objects,  the  abstracted  state  insures  against  distraction 
that  might  prevent  full  understanding.  It  is  only  exces- 
sive instability  or  too  great  and  inappropriate  immersion 
in  anything  that  should  be  guarded  against. 

The  Genesis  of  Attention.  —  Attention  must  be 
present  in  the  child  in  some  form  at  the  very  earliest 
stages;  the  change  with  years  is  primarily  in  the  con- 
ditions that  control  selection  and  the  constancy  with 
which  attention  is  kept  upon  one  object.  At  first,  selec- 
tion must  be  controlled  by  the  external  stimuli  and 
heredity.  The  infant  is  attracted  by  intense  stimuli  of 
any  sort  and  by  moving  objects.  Very  early,  experience 
shows  its  effect  and  the  child  begins  to  notice,  in  the 
chaos  of  the  new  and  unfamiliar,  objects  that  have  been 
seen  frequently.  From  this  time  on,  each  experience 
prepares  the  way  for  a  new  experience.  The  effect  of 
these  experiences  is  determined  by  the  closeness  of  the 
relation  of  the  experience  to  inherited  tendencies.  When 
they  oppose  heredity  the  effect  is  slighter  than  when  they 
aid  it.  At  this  stage  begins  in  an  indefinite  way  the 
development  of  interests.  These  are  to  grow  with  all 
learning  and  all  experience  and  must  change  and  develop 


SELECTION  AND  CONTROL  —  ATTENTION      127 

with  each  new  experience.  With  the  beginning  of  school 
years  or  earlier  comes  the  appreciation  of  duty  and 
other  rudimentary  social  demands.  At  this  stage  the 
child  makes  a  beginning  in  keeping  attention  fixed  upon 
the  more  unpleasant  thing  which  is  approved  by  society 
in  the  face  of  the  more  pleasant.  Training  in  attention 
of  this  sort  comes  at  first  through  seeing  the  advantages 
of  attending  in  harmony  with,  social  ideals  as  enforced 
through  discipline,  and  later,  obedience  to  the  calls  of 
duty  becomes  more  or  less  habitual  and  the  habit  con- 
stantly grows  and  changes  through  application  in  new 
fields.  In  terms  of  our  classification  attention  begins 
with  the  involuntary  and  the  hereditary  sort  of  non- 
voluntary  attention,  soon  the  other  non-voluntary  forms 
develop,  and  last  of  all  the  voluntary. 

The  second  fundamental  fact  that  is  to  be  used  in  the 
explanation  of  mental  processes  is  selection.  It  is  pos- 
sible to  select  sensations,  memories,  and  actions.  The 
conditions  that  lead  to  the  selection  are  the  same  in 
each  case.  They  are  to  be  found  in  the  intensity  of  the 
stimuli,  the  strength  of  the  memory  or  the  habit  on  the 
one  side,  and  in  the  momentary  attitude,  education  and 
heredity,  and  social  pressure  on  the  other.  Selection  in 
any  one  of  these  fields  is  accompanied  by  interest  if 
conditioned  by  education  or  heredity,  and  is  accom- 
panied by  diffuse  strain  sensations  that  give  rise  to  the 
feeling  of  effort  if  the  selection  is  controlled  by  duty. 
The  act  of  selection  is  called  attention  when  applied  to 
sensations ;  it  is  called  voluntary  control  of  ideas  when 
applied  to  recall ;  and  is  called  will  when  applied  to 
action.  So  far  we  have  considered  explicitly  only  the 


I28  ESSENTIALS   OF   PSYCHOLOGY 

control  of  sensation,  although  what  has  been  said  here 
of  conditions  and  accompaniments  holds  of  the  other 
processes  as  well,  as  will  be  made  clear  in  due  time.  It 
should  be  emphasised  that  the  terms  used  to  describe 
the  fact  are  less  important  than  the  fact.  The  fact  of 
selection  is  called  will  in  many  of  its  applications,  as  it 
has  been  called  attention  in  this  chapter.  There  should 
be  no  quarrel  as  to  whether  will  or  attention  is  the  more 
important,  as  each  is  but  a  word  used  to  designate  dif- 
ferent applications  of  this  fundamental  process  with  its 
conditions  and  accompaniments.  The  fact  is  essen- 
tial, the  name  is  a  matter  of  usage.  We  shall  make  use 
of  the  fact  in  connection  with  all  mental  operations. 

EXERCISES 

1.  Look  closely  at  a  point  on  an  evenly  illuminated  and  coloured 
wall.     Can  you  distinguish  any  difference  in  the  intensity  or  bright- 
ness of  the  point  looked  at  as  compared  with  the  surrounding  areas  ? 
Have  an  assistant  strike  several  notes  upon  some  instrument. 
Attend  first  to  one  then  to  another.     Does  the  attending  increase 
the  apparent  intensity  of  the  tone  or  merely  increase  its  clearness  ? 

2.  What  is  the  motive  for  attending  to  a  musical  selection? 
To  solving  these  problems  ?    To  a  loud  noise  ?    Why  do  you  no- 
tice your  own  name  whenever  it  is  seen  on  a  page  ?    Trace  the  acts 
of  attention  to  the  conditions  mentioned  in  the  text. 

3.  Recall  as  definitely  as  you  can  some  act  of  attention  that  in- 
volved effort.     Can  you  analyse  the  components  of  the  feeling  of 
effort  ?    Lift  a  heavy  weight  that  also  requires  effort.     Is  the  qual- 
ity the  same  as  in  the  effort  of  attention  ?   Can  you  trace  the  feeling 
to  any  sense-organ  ? 

4.  Watch  a  small  dot  so  far  away  that  it  can  just  be  seen.     Can 
you  see  it  all  the  time  ?    How  many  times  a  minute  does  it  come  and 
go? 


SELECTION   AND   CONTROL  —  ATTENTION  1 29 

5.  Try  to  keep  attention  upon  a  dot  when  near  enough  to  be  seen 
easily.     Can  you  watch  it  all  the  time  ?    Keep  a  list  of  the  mem- 
ories or  other  sensations  that  come  in  to  crowd  it  out.     How  many 
times  will  attention  wander  from  it  and  come  back  to  it  in  ten  sec- 
onds? 

6.  Have  an  assistant  prepare  a  set  of  cards  with  different  num- 
bers of  dots  upon  them.    Let  him  place  the  cards  face  down  upon  a 
table  and  show  them  one  after  another  for  an  instant  by  turning 
them  over  and  back.     What  is  the  largest  number  of  dots  that  may 
be  seen  at  a  single  glance  ?    Do  you  count  them  during  the  expos- 
ure or  from  memory  later  ? 

REFERENCES 

PILLSBURY  :  Attention,  chs.  i-v. 

ANGELL  :  Psychology,  ch.  v. 

TITCHENER:  Elementary    Psychology  of   Feeling  and  Attention, 

chs.  v-vii. 

JAMES  :  Principles  of  Psychology,  vol.  i,  ch.  xi. 
SEASHORE  :  Elementary  Experiments  in  Psychology,  ch.  xiii. 


CHAPTER  VI 
RETENTION  AND  ASSOCIATION 

ONE  other  sort  of  mental  content  must  be  considered 
before  we  can  regard  our  statement  of  the  materials  of 
consciousness  as  complete.  With  eyes  closed  and  with 
no  other  source  of  sense  stimulation,  one  has  conscious 
experiences.  The  mind  does  not  at  once  become  a  blank 
when  external  stimulation  is  removed,  and  at  any  moment 
.other  than  sensory  materials  are  intermingled  with  the 
sensory  processes.  You  may  now  recall  an  event  of  last 
year  in  very  much  the  same  form  as  that  in  which  it  was 
originally  experienced,  although  the  sense-organ  is  now 
not  excited  at  all.  You  can  see  the  landscape  in  its  origi- 
nal colours,  can  reinstate  the  temperature  of  a  summer 
day  although  it  is  now  winter,  may  in  fact  secure  any 
sort  of  experience  at  will.  These  experiences  in  their 
ultimate  qualities  are  of  the  same  character  as  the  sensa- 
tions. The  colours  are  the  spectral  colours,  the  tones 
are  the  tones  of  the  scale,  the  cold  is  the  same  old  cuta- 
neous sensation.  They  come  now,  however,  not  from  the 
sense-organs,  but  from  within.  To  indicate  the  similarity 
in  quality  to  sensation,  and  the  difference  in  immediate 
origin,  these  qualities  are  sometimes  called  centrally 
aroused  sensations.  A  little  observation  and  reflection 
show  that  in  every  case  these  processes  ultimately  origi- 
nate in  the  senses.  The  object  that  you  recall  is  the  same 


RETENTION   AND   ASSOCIATION  131 

object  that  you  saw  last  year.  On  occasion  you  may 
compare  the  memory  of  the  object  with  the  object  itself 
and  assure  yourself  of  the  similarity.  Even  when  the 
image  represents  nothing  that  has  been  seen  before,  the 
elements  of  which  it  is  composed  are  of  the  same  char- 
acter as  the  sensations.  The  elements  are  merely  rear- 
ranged in  new  combinations.  The  sensory  qualities, 
whether  peripherally  or  centrally  aroused,  are  like  the 
colours  upon  the  painter's  palette.  They  are  relatively 
few,  but  from  their  combinations  all  the  conscious  experi- 
ences may  be  obtained,  as  the  artist  may  paint  any  scene 
with  his  few  colours.  All  the  centrally  aroused  sensations, 
the  elements  of  memory  and  imagination,  come  originally 
from  the  senses.  They  are  retained  in  some  way  and 
reinstated  on  suitable  occasion.  An  understanding  of 
these  centrally  aroused  sensations  requires  an  answer  to 
three  questions:  (i)  how  are  they  retained  and  where 
are  they  between  the  time  of  entrance  and  of  their  rein- 
statement? (2)  under  what  circumstances  do  they 
return?  (3)  how  do  they  compare  in  quality  with  the 
original  sensations? 

Theories  of  the  nature  of  retention  of  experiences  have 
varied,  from  the  metaphor  of  the  ancients  that  mind  was 
like  wax  on  which  impressions  might  be  made  by  a  seal, 
to  the  equally  crude  physiological  theory  of  Spencer  that 
each  was  kept  in  a  single  nerve-cell.  The  generally 
accepted  theory  at  present  is  that  retention  is  a  physio- 
logical process  allied  to  habit.  Aristotle  suggested  that 
memories  were  due  to  the  repetition  on  recall  of  the  same 
movements  that  were  made  when  the  original  experience 
was  first  received.  Of  course  his  knowledge  of  the  physi- 


132  ESSENTIALS   OF   PSYCHOLOGY 

cal  organism  was  not  sufficient  to  carry  him  very  far  in 
his  theory,  but,  with  allowance  for  our  increased  knowl- 
edge of  the  nervous  system,  his  statement  does  very  well 
to-day.  Our  present  formulation  is  that  memory  consists 
in  the  rearousal  of  the  structures  that  were  active  origi- 
nally, or  in  the  reinstatement  of  the  same  activity  that 
was  involved  in  the  original  experience.  Whenever  a 
nerve-tract  is  active,  some  change  takes  place  in  it  that 
predisposes  it  to  act  in  the  same  way  again.  What  is 
left  in  the  nervous  system  is  only  this  predisposition  to 
renewed  activity,  not  an  idea  or  other  conscious  process. 
The  idea  comes  only  on  the  rearousal  of  structures  as  a 
result  of  the  predisposition.  Between  the  first  appear- 
ance and  the  rearousal,  the  predisposition  gives  no  sign 
of  its  presence.  At  this  moment  you  are  not  conscious  of 
all  the  memories  that  might  be  recalled  on  suitable  occa- 
sions. You  are  not  at  present  aware  of  the  facts  you 
learned  last  night  in  preparation  for  to-day's  recitation, 
although  you  will  be  able  to  recall  them  perfectly  when 
questioned  about  them. 

The  memories  probably  have  their  seat  in  the  same 
regions  of  the  cortex  that  are  active  in  the  original  per- 
ception. Injuries  of  a  sensory  area  usually  give  rise  to 
loss  or  disturbance  of  memories,  as  well  as  to  loss  of  the 
capacity  for  sensations.  In  addition,  injury  to  associa- 
tory  areas  may  have  an  effect  upon  memories.  It  is 
possible  that  in  some  individuals  the  sense-organ  is  excited 
as  well  as  the  central  nervous  system,  and  that  part  of 
the  memory  comes  from  the  retina,  or  from  the  skin 
where  the  impression  was  first  received.  The  muscles 
that  were  originally  excited  by  the  stimulus  may  also  be 


RETENTION   AND   ASSOCIATION  133 

in  slight  contraction  during  the  memory,  may  add  their 
quota  to  the  total  consciousness.  All  of  the  structures 
that  were  active  when  the  original  experience  was  received 
may  be  in  renewed  activity  during  the  recall.  It  is  prob- 
able that  the  change  that  is  induced  in  the  organism  at 
the  time  of  perception  has  its  seat  in  the  synapse  or  point 
of  contact  between  two  neurones.  At  least,  memory  ele- 
ments are  always  found  in  connection  with  each  other, 
they  are  established  together  and  return  together.  It 
is  probable  that  the  point  of  connection  between  the 
nervous  elements  involved  is  where  the  change  that  pre- 
disposes for  later  return  takes  place. 

In  this,  retention  is  closely  related  to  habit.  Habits, 
as  was  seen,  are  due  to  the  establishment  of  connections 
between  sensory  and  motor  neurones  by  a  change  that 
takes  place  at  the  synapse.  After  these  have  been 
frequently  connected,  the  stimulus  tends  to  reinstate  the 
act  whenever  it  appears.  Retention  of  ideas  has  exactly 
the  same  basis.  The  cells  involved  in  the  ideas  also  act 
together,  and  this  activity  produces  changes  in  the  syn- 
apses. Whenever  one  of  the  ideas  presents  itself  again, 
the  other  is,  or  tends  to  be,  reinstated.  Not  merely 
the  cortical  elements  are  rearoused  in  memory,  but  the 
whole  sensori-motor  tract  may  be  partially  active.  This 
brings  the  process  still  nearer  to  habit.  Memory  is  an 
habitual  response  in  which  the  greater  part  of  the  activity 
is  in  the  cortex.  The  activities  of  the  sense-organ  and  of 
the  muscles  are  subordinated  to  the  central  processes, 
while  in  habit  the  whole  sensori-motor  tract  is  active  in 
approximately  the  same  degree.  The  tendency  to  repeat 
an  action  once  made,  or  the  tendency  for  neurones  that 


134 


ESSENTIALS   OF   PSYCHOLOGY 


have  once  been  active  together  to  act  together  again 
when  either  is  aroused,  is  at  the  basis  of  both  processes. 
Thus,  when  a  stranger  enters  the  room,  I  stand  because 
the  sight  of  a  stranger  has  been  closely  connected  with 
rising.  But  at  the  same  moment  I  recall  vividly  a 
remark,  made  on  another  occasion,  by  a  person  of  similar 
appearance.  This  remark  has  been  connected  with  the 
sight  of  a  person  of  this  description,  in  very  much  the  same 
way  that  the  act  of  rising  has  been  connected  with  the 
entrance  of  any  stranger.  The  thought  might  have  been 
spoken  and,  then,  that  also  would  have  been  a  habit. 
The  only  difference  when  it  is  merely  recalled  is  that 
motor  accompaniments  are  left  off.  In  all  else  it  is  as 
much  a  habit  as  the  act  of  rising. 

Retention  may  also  be  related  to  the  visual  after- 
image. The  after-image  is  the  result  of  a  stimulus  upon 
the  retina  that  persists  for  a  short  time  after  its  cause  has 
ceased  to  act.  Cortical  cells  show  a  similar  tendency  to 
continue  in  action  for  a  period.  If  you  will  glance  out 
of  the  window  for  a  moment  and  then  close  the  eyes,  you 
will  notice  that  the  objects  you  saw  during  the  momentary 
glance  persist  for  a  few  seconds  with  sufficient  definite- 
ness  for  you  to  note  details  that  escaped  you  during  the 
actual  observation.  This  is  the  same  mental  photograph 
that  was  mentioned  in  the  chapter  on  attention  as  render- 
ing possible  the  perception  of  more  than  one  object 
during  a  very  brief  exposure.  It  has  the  same  explana- 
tion as  the  positive  after-image.  Like  the  after-image 
it  is  the  result  of  the  persistence  of  activity  in  the  neurones 
after  the  stimulus  is  removed.  It  is  sometimes  called  the 
memory  after-image  or  primary  memory,  or  more  recently 


RETENTION    AND    ASSOCIATION  135 

the  perseveration  tendency.  The  ordinary  memory,  or 
reinstatement  after  the  primary  memory  has  lapsed, 
may  be  looked  upon  as  a  renewal  of  the  same  activity 
of  the  cells  that  was  induced  by  the  stimulus  and  that 
persisted  during  the  primary  memory.  To-morrow 
when  you  recall  what  you  saw  as  you  looked  from  the 
window,  you  will  induce  in  the  cortical  cells  the  same  sort 
of  activity  that  they  showed  when  you  were  looking  and 
during  the  memory  after-image. 

Recall  is  always  through  Associated  Experiences.  — 
The  answer  to  our  second  question  concerning  centrally 
aroused  experiences,  of  how  they  are  recalled,  is  found 
in  the  laws  of  association.  These  laws  assert  that  all 
recall  is  due  to  the  preceding  mental  process.  This 
process  is  effective  in  calling  back  the  ideas  because  of 
connections  that  have  been  developed  between  them  at 
some  earlier  time.  The  idea  that  was  in  mind  a  moment 
ago  and  the  idea  that  it  recalls  now  must  have  been 
experienced  together  at  some  time,  if  the  one  is  to  recall 
the  other.  The  control  of  recall  by  these  earlier  experi- 
ences and  connections  may  be  seen  in  any  train  of  ideas. 
If  one  will  record  the  elements  of  an  uncontrolled  train 
of  thought,  it  will  be  seen  that  each  element  is  connected 
with  the  following  by  virtue  of  both  having  been  experi- 
enced together  at  some  time.  A  girl  passing  my  window 
suggests  the  house  I  saw  her  going  into  yesterday.  That 
suggests  the  stages  in  building  the  house ;  that,  in  turn, 
the  sound  of  hammering  that  woke  me  this  morning ; 
and  this  again  the  protest  of  one  neighbour  to  another 
who  had  been  frequently  chopping  kindling  wood  at  an 
unreasonably  early  hour  in  the  morning.  A  revery  of 


I7>6  ESSENTIALS    OF    PSYCHOLOGY 

this  sort,  when  started,  may  run  through  successive 
links  until  disturbed  by  some  duty  or  other  distraction. 
A  study  of  a  train  of  ideas  will  show  that  each  member 
of  the  train  has  been  connected  with  the  preceding  and 
succeeding  links  at  some  earlier  period.  It  is  evident, 
however,  that  in  the  train  just  described,  the  connections 
are  of  different  sorts  and  are  due  to  different  earlier 
connections.  The  first  two  associates  are  the  result  of 
observing  two  things  at  the  same  time.  The  last  two 
turn  about  some  element  that  is  common  to  both  of  the 
terms,  although  the  terms  as  a  whole  have  never  been 
in  consciousness  together.  This  difference  makes  neces- 
sary a  classification  of  the  forms  of  connection. 

The  Laws  of  Association.  —  The  traditional  classifica- 
tion of  association  has  been  traced  back  to  Aristotle, 
and  recognised  four  sorts  of  association :  association  by 
contiguity,  by  succession,  by  similarity,  and  by  contrast. 
The  first  two  classes  have  an  altogether  different  explana- 
tion from  the  last  two.  The  first  two  refer  the  connections 
to  the  relations  at  the  time  the  connections  were  formed, 
the  last  two  classify  by  the  nature  of  the  experiences  at  the 
time  of  recall.  Association  by  contiguity  means  merely 
that  if  two  objects  are  perceived  at  the  same  time,  one 
is  always  likely  to  enter  consciousness  if  the  other  presents 
itself.  Association  by  succession  asserts  that  if  two  ideas 
have  been  experienced  in  succession,  the  second  will  be 
suggested  by  the  first  whenever  it  comes  to  consciousness. 
In  the  illustration  of  the  preceding  paragraph,  the  girl 
suggests  the  house  because  I  have  seen  them  together. 
The  best  illustration  of  successive  association  is  found 
in  the  ordinary  rote  learning.  The  words  that  are  re- 


RETENTION    AND    ASSOCIATION  137 

peated  in  succession  return  in  succession  when  the  first 
word  is  suggested.  Association  by  similarity  includes 
instances  of  recall,  in  which  the  idea  suggested  is  in  some 
way  similar  to  the  preceding.  Such  is  found  in  the  build- 
ing of  the  house  suggesting  the  hammering  that  awakened 
me,  or  perhaps,  more  strictly,  the  connection  shown  when 
the  hammering  suggested  the  protest  of  a  neighbour 
against  a  disturbance  of  a  similar  kind.  Association  by 
contrast  covers  the  cases  in  which  the  two  ideas  involve 
opposite  qualities  as  when  black  suggests  white,  or  big, 
little. 

These  original  laws  of  association  are  largely  merely 
descriptive  of  the  sorts  of  ideas  that  succeed  each  other 
in  consciousness.  The  laws  do  not  indicate  the  reasons 
for  the  succession  or  the  causes  for  the  entrance  of  the 
different  ideas ;  they  serve  only  to  classify  the  connec- 
tions when  they  are  once  effective.  If  one  ask  why 
one  idea  recalls  the  one  that  entered  consciousness  with 
it,  or  the  one  that  succeeded  it  when  last  it  was  conscious, 
one  must  turn  back  to  the  study  of  the  nervous  system. 
In  these  terms  our  law  states  that  if  two  neurones  are 
active  simultaneously  or  in  immediate  succession,  some 
connection  is  established  between  them,  of  such  a  char- 
acter that  if  one  be  excited  in  any  way,  the  excitation 
spreads  to  the  other.  The  point  of  connection  is,  as  has 
been  said  frequently,  the  synapse.  Just  as  in  habit, 
the  action  that  leads  to  the  excitation  of  two  neurones  at 
the  same  time  or  in  succession  decreases  the  resistance 
of  the  synapse ;  so,  too,  the  simultaneous  action  of  two 
cortical  cells  leads  to  a  diminution  of  resistance.  This 
increased  closeness  of  connection  makes  possible  the 


138         ESSENTIALS  OF  PSYCHOLOGY 

spread  of  any  activity  from  one  to  the  other.  When  one 
learns  the  first  letters  of  the  alphabet,  the  impulse  spreads 
from  the  neurone  corresponding  to  '  a  '  to  the  neurone 
corresponding  to  '  b,'  and  as  a  result  of  numerous  repeti- 
tions the  two  neurones  grow  together  to  such  a  degree  that 
whenever  '  a  '  is  suggested,  the  excitation  spreads  to  the 
neurone  that  corresponds  to  '  b,'  and  that  is  excited  also. 
The  change  in  the  synapse  as  a  result  of  use  is  the  explana- 
tion of  association,  as  of  habit.  Association  by  contiguity 
and  succession  is  the  expression  of  this  simple  and  familiar 
neurological  function. 

Not  so  immediate  is  the  explanation  of  association  by 
similarity.  Similarity  is  not  itself  a  force,  nor  is  it  pos- 
sible to  find  simple  physiological  correlates  for  it.  As 
a  matter  of  fact,  the  principles  that  are  really  effective 
in  recall  in  these  cases  have  little  to  do  with  similarity. 
The  ordinary  idea  is  not  a  simple  element  of  consciousness 
but  is  a  complex  of  many  centrally  aroused  sensations. 
The  mechanism  of  recall  consists  in  replacing  certain  of  the 
elements  of  the  first  idea  by  others  to  constitute  the  new 
idea.  Thus  the  replacement  of  the  idea  of  the  disturbing 
hammering,  by  the  idea  of  the  neighbour's  protest  at 
another  form  of  disturbance  under  the  same  circum- 
stances, may  be  regarded  as  due  to  a  shift  of  ideas  about 
'  early-morning-noise-that-disturbs-sleepers  '  as  a  centre. 
The  elements,  that  have  to  do  with  hammering  in  building 
the  house,  drop  out,  and  the  persisting  elements,  that  con- 
stitute the  early  morning  disturbance  idea,  are  retained. 
These  by  the  law  of  contiguity  or  succession  waken 
the  remaining  elements  of  the  incident  described  by  my 
neighbour.  The  whole  process  is  the  dropping  out  of 


RETENTION   AND   ASSOCIATION  139 

certain  elements,  and  the  recall  by  the  others  of  new 
elements  that  have  been  connected  with  them.  The 
common  element  at  once  makes  possible  the  entrance  of 
the  second,  and  gives  similarity  to  the  two  ideas.  If 
this  be  translated  into  nervous  terms,  the  first  idea 
corresponds  to  the  action  of  a  considerable  group  of 
neurones.  The  shift  to  the  second  idea  consists,  first, 
in  the  cessation  or  diminution  in  the  activity  of  certain 
elements  of  the  mass,  while  others  continue  to  act  with 
full  intensity.  These  cells,  that  continue  active,  rouse 
to  activity  the  other  group  of  cells  with  which  they  have 
also  been  active  earlier,  and  with  that  the  incident  of  the 
protest  against  chopping  in  the  early  morning  comes 
to  consciousness.  The  simple  physiological  laws  are  the 
same  here  as  in  the  earlier  case ;  the  only  added  feature 
is  the  dropping  out  of  the  activity  of  some  elements, 
while  the  others  continue  active.  Wundt  has  called  this 
sort  of  recall  association  by  identity,  since  it  is  the  iden- 
tical element  in  each  idea  that  determines  the  course  of 
recall.  James  calls  the  process  focalised  recall,  but  both 
agree  on  the  essentials  of  the  process  as  given  above. 

Both  sorts  of  association  involve  the  same  principle, 
but  there  is  a  slight  difference  in  its  application.  This 
is,  that  use  tends  to  connect  neurones,  or  that  mental 
elements  that  appear  together  tend  to  return  together. 
The  apparent  difference  between  the  two  classes  serves 
merely  to  emphasise  the  fact  that  ideas  are  neurologically 
and  psychologically  always  complex.  The  ideas  that  are 
recalled  by  contiguity  or  succession  are  not  simple,  but 
the  mass  of  elements  may  be  regarded  as  disappearing 
or  appearing  as  a  whole  rather  than  as  dissolving  one  into 


140  ESSENTIALS    OF   PSYCHOLOGY 

the  other,  as  in  the  so-called  association  by  similarity. 
In  both  cases  one  must  distinguish  between  the  unit  for 
thought  and  the  unit  for  physiological  action.  For 
thought,  the  idea  is  the  unit ;  one  is  concerned  only  with 
things  and  with  their  representatives  as  wholes.  Associa- 
tion on  the  contrary  is  always  between  the  elements  that 
correspond  to  the  activity  of  neurones.  Their  connec- 
tions alone  determine  the  way  in  which  ideas  shall  succeed 
each  other,  and  how  they  shall  dissolve,  one  into  the  other. 
The  older  laws  of  association  considered  only  the  relations 
between  the  ideas  as  wholes ;  any  dynamic  explanation 
must  consider  primarily  the  connections  between  the 
elements.  They  explained  by  similarity  what  the  more 
modern  men  explain  by  the  shifting  of  associates  about 
some  persisting  element  as  a  core.  Both  are  true,  but 
one  is  a  description  of  the  ideas  after  the  recall,  the  other 
is  the  real  explanation  of  the  recall.  Of  the  two  sorts  of 
association,  it  is  probable  that  there  is  in  every  case 
something  of  the  gradual  disappearance  of  one  idea,  and 
the  gradual  reappearance  of  the  other.  In  general  the 
more  mechanical  sorts  of  recall,  the  effects  of  rote  learning, 
etc.,  involve  contiguity  and  succession,  while  the  more 
intelligent  forms  of  thinking  make  the  association  by 
identity  more  prominent.  Association  by  contrast  of 
the  older  schools  is  also  to  be  explained  as  due  either 
to  the  frequency  with  which  things  that  contrast  are  per- 
ceived together,  or  to  the  shifting  of  elements  about  some 
common  unit.  Probably  each  explains  certain  instances. 
The  contrast  in  many  cases  would  not  be  noticed  unless 
the  elements  were  in  consciousness  together.  Dark  is 
appreciated  only  when  near  light,  rich  only  when  experi- 


RETENTION   AND   ASSOCIATION  141 

enced  with  poor.  On  the  other  hand,  there  is  always 
something  in  common  between  contrasting  qualities. 
Rich  does  not  contrast  with  dark,  nor  light  with  small, 
because  they  have  no  common  qualities.  If  one  looks 
to  the  real  causes  of  recall  rather  than  to  a  description  of 
the  ideas  that  succeed  each  other,  association  by  contrast 
is  really  an  instance  either  of  association  by  contiguity, 
or  of  association  by  succession.  All  recall  is  due  to  the 
simple  fact  that  ideas  that  are  in  consciousness  together 
tend  to  return  together.  The  various  classes  are  but 
different  applications  of  this  one  principle. 

While  recall  depends  upon  association,  it  is  still  a  ques- 
tion why  one  rather  than  another  of  the  many  associates 
that  are  possible  comes  to  consciousness.  Practically 
every  idea  has  been  connected  at  some  time  with  a  great 
many  other  ideas,  but  at  any  one  time  it  will  arouse  only 
one  of  these  associates.  The  selection  of  one  from  among 
these  possible  associates  has  approximately  the  same 
conditions  as  the  selection  of  sensations  in  attention. 
Here  again  we  may  divide  the  conditions  into  two  classes, 
objective  and  subjective.  Among  the  objective  condi- 
tions, we  find  the  influences  that  determine  the  strength  of 
the  physiological  connection  between  the  neurones.  These 
are  four  in  number:  (i)  the  strength  of  the  original 
excitation;  (2)  the  number  of  times  the  two  have  been 
active  together;  (3)  the  recency  of  the  original  connec- 
tion; and  (4)  whether  it  was  the  first  association  that  had 
been  made  with  the  suggesting  idea.  The  intensity  of 
the  original  excitation  depends  upon  three  factors: 
(i)  upon  the  intensity  of  the  physical  stimuli  that  gave 
rise  to  the  original  experiences;  (2)  upon  the  degree  of 


142          ESSENTIALS  OF  PSYCHOLOGY 

attention  that  was  given  at  the  time;  and  (3)  upon  the 
emotional  condition  of  the  individual  at  the  time  of  learn- 
ing. Each  of  these  can  easily  be  seen  to  have  an  effect 
from  your  own  experience.  Two  weak  experiences 
will  be  less  likely  to  be  associated  than  stronger  ones. 
Much  more  important  is  the  effect  of  attention.  Inat- 
tentive reading  is  only  slightly  effective.  Attention  at 
the  moment  of  the  original  reading  may  make  faint  im- 
pressions more  effective  than  intense  impressions.  In 
fact  it  might  be  questioned  whether  the  intensity  of  the 
stimulus  had  any  effect,  except  as  it  served  to  attract 
attention.  The  effect  of  emotion  is  very  closely  related 
to  attention.  If  the  original  experiences  were  attended 
by  marked  emotion,  the  likelihood  of  recall  is  increased. 
The  others  of  the  objective  conditions  of  recall  require 
little  comment.  The  strength  of  the  connection  grows 
regularly  with  repetitions,  and  falls  away  with  the  lapse 
of  time.  Of  two  associates,  the  one  first  made  seems  to 
have  an  advantage  over  the  other.  This  is  one  explanation 
of  the  fact  that  events  of  childhood  are  more  frequently 
recalled  than  those  of  later  life.  Each  of  these  objective 
conditions  is  effective,  because  it  helps  to  determine  the 
strength  of  the  connection  between  the  different  elements 
in  the  nervous  system. 

While  these  objective  or  physiological  connections  are 
essential  to  all  recall,  and  play  an  important  part  in  deter- 
mining the  selection  of  one  from  many  associates,  they 
cannot  be  the  only  determinants.  Were  they  the  only 
factors  in  the  selection,  the  course  of  thought  would  show 
no  flexibility  ajid  no  spontaneity.  Only  one  associate 
can  be  physiologically  strongest  at  any  moment.  In 


RETENTION   AND   ASSOCIATION  143 

actual  experience  we  see  an  idea  recalling,  now  one  idea 
and  now  another ;  we  are  ever  and  anon  preferring  a  faint 
associate  to  a  strong,  an  old  to  a  new.  What  gives  this 
variety  and  flexibility  to  ideas  is  the  group  of  subjective 
conditions.  These  are  practically  the  same  as  the  sub- 
jective conditions  in  attention.  The  first  is  the  attitude 
or  purpose  of  the  moment.  If  you  are  solving  one 
problem,  the  associates  that  are  suited  to  that  problem 
will  be  recalled ;  if  you  are  solving  another  problem  and 
have  the  same  idea  in  mind,  it  will 'recall  another  idea. 
For  example,  if  you  see  in  your  account  book  two  numbers 
written  one  above  the  other,  you  will  add  in  one  case, 
you  will  subtract  in  the  other.  Whether  you  add  or 
subtract  will  depend  upon  the  context,  upon  the  problem 
that  is  set  you  by  the  earlier  stages  in  the  accounting. 
If  you  are  dealing  with  two  expenditures,  you  add ; 
if  dealing  with  a  balance  and  an  expenditure,  you  sub- 
tract. In  this  case,  the  sum  is  one  associated  idea  that 
the  two  numbers  might  suggest,  the  difference  another 
associated  idea,  and  which  shall  enter  depends  upon  the 
purpose  of  the  moment.  Similarly,  if  you  read  a  series  of 
adjectives  to  a  person  with  the  request  to  name  opposites, 
you  will  get  one  series  of  associates ;  if  you  ask  him  to  give 
synonyms,  you  will  get  another  series.  Here  you  set  the 
task,  and  it  leads  at  once  to  the  right  associate.  Probably 
in  most  cases  the  attitude  is  not  at  all  conscious,  is  not 
appreciated  by  the  thinker.  When  asked  in  a  class  in 
psychology  what  is  a  sensation,  one  at  once  thinks  of 
the  psychological  definition.  The  same  question  by  a 
child  who  was  reading  the  headline  of  a  newspaper 
brings  to  mind  an  entirely  different  answer.  One  is  not 


144  ESSENTIALS   OF   PSYCHOLOGY 

aware  of  the  psychological  attitude,  but  it  is  suggested 
by  the  place ;  while  the  sight  of  the  newspaper  gives  the 
newspaper  attitude  just  as  certainly  and  just  as  uncon- 
sciously. James  illustrates  the  influence  of  attitude  by 
the  effect  of  the  context  in  two  lines  of  verse.  The  same 
word,  when  it  occurs  in  different  lines  of  verse,  will  recall 
different  associates.  Thus  the  word  ages  occurs  in  the 
two  lines  from  Locksley  Hall  — 

"I,  the  heir  of  all  the  ages,  in  the  foremost  files  of  time" 
and 

"  For  I  doubt  not  through  the  ages  one  eternal  purpose  runs." 

One  does  not,  however,  make  a  mistake  and  supply  '  one 
eternal '  after  the  '  ages  '  in  the  first  line,  nor  '  in  the  .  .  .' 
after  the  '  ages  '  in  the  second.  The  preceding  words 
and  the  general  purpose  in  quoting  insure  the  recall 
of  the  right  associates,  whether  strong  or  weak.  The 
wider  setting,  the  attitude  or  purpose,  plays  an  important 
part  in  determining  the  course  of  recall. 

Of  the  other  conditions  that  were  seen  to  play  a  part 
in  the  selection  of  sensations  that  may  enter  conscious- 
ness, education,  social  pressure,  and  heredity  have  their 
effect  in  the  control  of  recall.  Education  is  harder  to  dis- 
tinguish from  the  preparation  of  connections  here  than  in 
attention.  Its  most  important  influence  is  probably  in 
grouping  experiences  that  may  be  aroused  later  as  units, 
and  so  constitute  the  basis  for  attitudes.  An  attitude 
or  purpose  is  very  largely  just  the  response  of  an  entire 
group  of  neurones  that  serves  to  facilitate  the  recall  of 
all  members  of  the  group  when  the  group  as  a  whole  is 
aroused.  One's  purposes  grow  out  of,  and  are  dependent 


RETENTION   AND   ASSOCIATION  145 

upon,  training  and  education.  It  is  in  preparing  for  these 
attitudes  that  education  exercises  its  most  important 
influence  upon  the  selection  of  associates.  Social  press- 
ure here,  as  in  attention,  is  the  most  important  element 
in  enforcing  duty.  One  is  held  to  the  disagreeable  task 
by  considerations  of  what  others  would  think  if  the  work 
be  not  finished  when  it  would  be  pleasanter  to  let  the 
train  of  thought  wander  at  will.  A  student  in  writing 
an  exercise  wanders  away  for  a  moment  in  a  day  dream, 
but  as  soon  as  he  is  reminded  of  the  task,  the  ideas 
connected  with  the  writing  reassert  themselves.  The 
course  of  association  is  held  to  the  task  until  the  work  is 
completed.  The  considerations  that  enforce  this  return 
to  the  unpleasant  course  of  thought  are  primarily  social. 
It  is  probable  that  heredity  has  some  influence  in  directing 
the  course  of  thought.  Thoughts  of  a  certain  kind  are 
pleasant  because  of  the  natural  endowment  of  the  indi- 
vidual, just  as  certain  objects  are  pleasant.  In  brief, 
the  conditions  that  select  one  associate  from  the  many 
possible  ones  are  approximately  the  same  as  the  conditions 
that  select  one  from  among  the  many  possible  sensations 
that  present  themselves  in  the  outside  world. 

The  Physiological  Basis  of  the  Control  of  Ideas.  — 
The  physiological  explanation  of  the  influence  of  the  sub- 
jective elements  upon  the  course  of  recall  must  be  found 
in  the  influence  of  wider  masses  of  neurones  than  those 
involved  in  the  direct  arousal  of  the  memory.  Let  us 
assume  that  one  is  attending  to  a  pencil,  and  that  several 
associates  have  been  connected  with  it.  Let  us  assume 
that:  A  represents  the  neurones  that  are  involved  in 
thinking  of  the  pencil,  and  connected  with  it  are  B,  C,  D, 


146  ESSENTIALS   OF   PSYCHOLOGY 

and  E.  B  is  the  neurone  group  connected  with  the  idea 
of  graphite  mines;  C,  with  the  thought  of  a  pen;  D, 
with  the  picture  of  a  cedar  forest ;  E,  with  the  memory  of 
the  shop  where  it  was  obtained,  etc.  Let  us  assume  that 
the  strongest  connection,  as  a  mere  physiological  process, 
is  with  the  shop,  but  that  you  are  writing  of  the  crystal 
forms  of  carbon.  The  neurones  corresponding  to  the 
means  of  obtaining  graphite  have  been  predisposed 
to  excitation  by  the  writing,  —  the  group  B  would  be 
partially  aroused.  The  preparedness  of  B  for  excitation 
from  this  other  connection  is  sufficient  to  overcome  the 
greater  physiological  strength  of  E,  and  you  think  of 
graphite  mines,  rather  than  of  any  of  the  other  things 
that  were  possible.  At  any  moment  the  course  of 
thought  will  be  determined  by  these  antecedent  and 
related  thoughts,  or  by  the  physiological  activities  that 
correspond  to  them. 

All  recall  depends  upon  associations  that  have  been 
formed  by  the  experiences  of  the  individual.  At  any 
moment  recall  is  limited  to  the  ideas  that  have  been 
connected  with  the  idea  then  in  mind.  Of  the  many 
things  that  have  been  connected,  that  one  will  be  chosen 
that  is  physiologically  strongest  or  that  is  most  in  har- 
mony with  the  purpose  of  the  moment.  In  many  cases 
of  mechanical  recall  it  is  the  strength  of  the  association 
that  is  most  important  in  determining  the  course  of  ideas, 
but  in  ordered  thought  the  subjective  conditions  are  more 
prominent.  In  a  day  dream  the  mechanical  associates 
will  be  the  more  important ;  in  writing  of  a  serious  sort, 
or  in  speaking,  the  attitude  and  the  problem  will  pre- 
dominate. Even  in  connected  thinking  irrelevant  ideas 


RETENTION   AND   ASSOCIATION  147 

will  frequently  insert  themselves.  If  these  are  carefully 
examined,  it  will  be  seen  that  these  interjected  irrelevant 
ideas  are  introduced  because  of  the  strength  of  the  objec- 
tive connection  between  them  and  the  preceding  idea  in 
the  train.  The  objective  connections  are  sufficiently 
strong  to  prevail  against  subjective  control.  No  idea 
can  be  recalled  unless  some  idea  that  has  been  associated 
with  it  is  present  at  the  moment.  One  cannot  arbitrarily 
get  back  ideas  without  natural  antecedents.  This  causes 
no  inconvenience,  because  one  does  not  ordinarily  feel 
the  need  of  an  idea  without  being  able  to  recall  it.  The 
desire  for  recall  ordinarily  serves  as  a  sufficient  suggestion 
to  effect  it.  Given  the  old  connections  that  make  pos- 
sible the  recall  of  different  ideas,  the  subjective  conditions 
of  attitude  or  purpose,  social  pressure,  and  heredity, 
together  with  the  setting,  internal  and  external,  select 
from  the  possible  associates  the  one  that  suits  the  need 
of  the  moment. 

The  Qualities  of  centrally  aroused  Sensations.  —  The 
elementary  qualities  of  memory,  imagination,  and  reason- 
ing are  very  similar  to  the  qualities  of  sensations  that 
come  directly  from  the  sense-organ.  If  one  thinks  of  a 
red  surface,  one  may  have  an  image  that  is  in  every  respect 
like  the  original  perception.  The  colour  is  red,  the  texture 
of  the  surface  may  be  the  same  as  the  texture  of  some 
substance  that  has  the  colour  in  reality.  While  the  quali- 
ties are  the  same  as  in  sensation,  there  are  nearly  always 
sufficient  differences  to  prevent  one  from  mistaking  a 
memory  image,  or  image  of  imagination,  for  the  real 
object.  That  this  mistake  is  not  made  more  frequently 
is  due  to  at  least  three  factors:  (i)  centrally  aroused 


148          ESSENTIALS  OF  PSYCHOLOGY 

sensations  are  ordinarily  less  intense  than  the  real  sensa- 
tions ;  (2)  they  have  certain  characteristic  qualitative 
differences ;  (3)  they  do  not  harmonise  with  the  other 
objects  that  are  seen  at  the  moment.  The  first  criterion 
is  ordinarily  sufficient,  but  fails  when  the  images  become 
very  intense,  or  the  external  stimulus  is  very  faint.  The 
great  vividness  of  the  images  comes  only  rarely  and  usu- 
ally in  abnormal  individuals  or  under  abnormal  condi- 
tions. Faint  intensity  of  external  stimulation  may  be 
obtained  at  will.  In  a  series  of  experiments  by  Kiilpe, 
individuals  were  seated  in  a  dark  room  and  asked  to  decide 
whether  at  a  signal  the  colours  that  they  saw  upon  a  screen 
were  real  or  imagined.  Sometimes  faint  colours  were 
thrown  upon  the  screen  and  at  other  times  no  objective 
change  was  made.  Under  these  conditions,  every 
observer  made  mistakes.  Ordinarily  the  mistakes  con- 
sisted in  asserting  that  colours  were  seen  when  none  were 
shown.  The  merely  imagined  qualities  were  mistaken 
for  objective  qualities.  When  questioned  as  to  how  they 
distinguished  one  from  the  other,  the  observers  gave  a 
list  of  the  characteristics  that  aided  them.  The  subjec- 
tive processes  were  indefinite  in  outline,  were  thin  or  net- 
like,  they  moved  at  random,  they  persisted  when  the  eyes 
were  closed  and  moved  with  the  eyes,  they  left  no  after- 
images. The  real  sensations  were  definite  in  quality 
and  outline,  vanished  on  closing  the  eyes,  remained  sta- 
tionary as  the  eyes  moved,  and  left  after-images.  The 
differences  are  on  the  whole  insignificant,  and  even  those 
that  were  mentioned  were  not  constant  for  all  individuals. 
In  quality,  images  are  not  very  different  from  sensations. 
More  important  as  a  means  of  distinguishing  one  from 


RETENTION   AND   ASSOCIATION  149 

the  other  in  practice  is  the  harmony  of  images  with  the 
preceding  train  of  thought,  and  their  lack  of  harmony 
with  the  events  of  the  outside  world.  If  one  should  look 
up  suddenly  and  see  what  appeared  to  be  the  figure  of  a 
person  known  to  be  remote  but  whom  one  had  been  think- 
ing about  just  before,  one  would  at  once  appreciate  the 
figure  to  be  an  image.  This  would  be  all  the  more  certain 
if  no  footsteps  had  been  heard,  and  the  wall  could  be  seen 
through  the  image.  The  figure  would  be  seen  to  be  a 
natural  result  of  the  thought  processes  but  altogether  out 
of  harmony  with  the  external  events.  The  decision  as 
to  whether  a  mental  process  is  of  central  or  of  peripheral 
origin  is  most  frequently  decided  in  terms  of  its  agree- 
ment with  one  or  the  other  course  of  events,  although 
intensity  and  the  peculiar  penetration  or  vividness  of  the 
sensation  nearly  always  contribute  their  share.  A  third 
criterion  is  often  furnished  by  the  direction  in  which 
memory  images  are  projected.  The  image  will  be 
directed  backward  if  centrally  aroused,  as  opposed  to 
the  ordinary  outward  and  forward  reference  of  the  real 
visual  sensation.  Objects  when  recalled  may  be  seen 
as  if  they  were  on  a  surface  some  distance  back  of  the 
head.  Others  project  imagined  objects  to  the  right  or  to 
the  left.  Here  they  will  not  be  confused  with  the  sensory 
impressions.  It  is  possible  that  images  can  be  projected 
outward  and  forward  so  as  to  have  a  position  among 
objects  actually  seen.  One  individual  always  sees  re- 
membered or  imagined  events  projected  in  colours  upon 
the  wall  of  the  room,  and  many  can  give  these  images 
any  desired  position  in  the  visual  field.  These  are  mere 
personal  idiosyncrasies.  Where  the  central  processes 


150  ESSENTIALS   OF   PSYCHOLOGY 

are  thus  habitually  given  a  direction  different  from  that 
given  sensations,  the  direction  is  a  result  of  the  distinc- 
tion that  is  made,  rather  than  a  means  of  distinguishing 
them  from  external  objects.  The  decision  as  to  whether 
the  process  is  of  external  or  internal  origin  is  practically 
always  immediate  and  without  hesitation ;  one  does  not 
even  appreciate  that  a  decision  has  been  made. 

While  the  memory  images  are  of  the  same  general 
qualities  as  the  sensations,  they  are  certainly  much  less 
rich  in  qualities.  The  number  of  pure  colours  that  an 
individual  can  recall  is  probably  limited  to  a  dozen  or 
twenty,  as  compared  with  the  one  hundred  fifty  or  two 
hundred  that  may  be  discriminated  in  the  spectrum. 
The  qualities  in  the  other  senses  are  similarly  limited. 
Not  only  are  the  qualities  of  any  one  sense  that  may 
be  recalled  relatively  few  as  compared  with  sensations, 
but  most  individuals  are  restricted  for  their  memory 
material  to  one,  or  at  most  but  two  or  three,  of  the 
senses.  Most  numerous  are  the  individuals '  who  re- 
member in  visual  terms.  A  visualiser  of  the  complete 
type  will  recall  only  the  pictures  of  objects.  As  he 
thinks  of  the  water  running  from  a  faucet,  he  can  see  the 
water  fall,  see  it  splash,  but  has  no  trace  of  the  sound. 
The  whole  event  is  noiseless  in  memory.  Everything 
that  he  remembers  must  be  translated  into  images. 
More  rare  is  the  auditory  memory.  Individuals  of  this 
type  lack  all  but  the  sounds  in  any  memory  process. 
An  event  will  be  recalled  only  in  terms  of  the  sounds 
that  were  connected  with  it.  In  other  individuals  mem- 
ories are  restricted  to  the  movements  that  were  made  in 
connection  with  the  events.  These  movements  may  be 


RETENTION   AND   ASSOCIATION  151 

memories,  or  the  movement  may  be  partly  reinstated. 
One  might  translate  any  experience  into  words,  for  ex- 
ample, and  remember  the  words  by  the  movements  that 
would  be  required  to  speak  them.  Smell,  taste,  and  the 
other  lower  senses  alone  would  not  suffice  to  recall  all 
sorts  of  experiences;  where  present  at  all  in  memory, 
they  are  subordinate  to  the  three  senses  just  mentioned. 
Usually  the  memories  are  not  confined  to  one  of  the  three 
principal  senses,  but  some  one  of  these  is  dominant,  and 
one  or  both  of  the  others  will  contribute  to  the  memory 
of  particular  experiences.  One  will  have  a  visual  mem- 
ory of  things  seen  and  will  remember  sounds,  either  in 
auditory  terms,  or  in  terms  of  the  feeling  in  the  vocal 
organs  that  would  arise  if  the  sounds  were  imitated. 
In  other  individuals,  all  of  the  senses  may  be  represented, 
but  some  much  more  vividly  than  others.  In  no  case  are 
all  senses  equally  prominent  in  recall. 

Obviously,  there  must  be  a  fairly  close  relation  be- 
tween the  accomplishments  of  the  individual  and  his 
memory  type.  It  would  be  very  difficult  to  imagine  a 
painter  who  could  not  recall  colours  and  forms,  or  a  musi- 
cian who  had  no  memory  for  tone.  As  a  matter  of  fact, 
most  great  musicians  are  of  the  auditory  type  and  most 
painters  are  visualists.  In  more  commonplace  affairs 
the  memory  type  plays  an  important  part.  A  pupil  who 
has  no  visual  imagery  finds  difficulty  in  spelling.  The 
methods  of  learning,  too,  soon  adapt  themselves  to  the 
memory  type.  It  should  not  be  supposed  from  this  that 
powers  of  observation  are  similarly  restricted.  One  of 
the  visual  type  may  understand  a  lecture  fully  as  well  as 
his  fellow  of  auditory  mind ;  as  he  understands,  however, 


152          ESSENTIALS  OF  PSYCHOLOGY 

he  translates  what  is  said  into  pictures  and  remembers 
these.  Recognition  of  the  voice  may  be  as  accurate,  also. 
The  visual-minded  individual  will  know  the  voice  of  a 
friend  when  he  hears  it  again,  although  he  may  not  be 
able  to  recall  it  at  all.  Apparently  memory  types  may  be 
trained,  and  undergo  changes  with  age.  Experiments  in 
developing  memory  types  that  were  originally  weak  have 
met  with  some  success,  although  the  course  of  training 
must  be  long.  Imagery  tends  to  become  less  concrete 
and  definite  with  advancing  years,  particularly  if  the 
individual  devotes  himself  to  pursuits  requiring  abstract 
thought.  Galton  found  that  English  men  of  science  had 
very  little  definite  imagery.  Most  thinking  was  in  verbal 
imagery  or  in  other  more  abstract  forms  of  thought.  It 
seems  that  the  general  tendency,  as  men  deal  more  and 
more  with  principles  and  less  and  less  with  particulars, 
is  toward  a  disappearance  of  detailed  imagery,  and  its 
replacement  by  symbols.  The  objects  are  represented 
in  memory  by  imagery  that  has  less  and  less  resemblance 
to  them,  but  which  is  better  adapted  to  the  needs  of  quick 
and  accurate  thought. 

Summary.  —  Our  third  fundamental  mental  fact  is 
that  impressions  received  from  the  senses  are  retained  in 
the  nervous  system  as  dispositions  to  re-excitation. 
They  return  when  some  experience  that  has  been  con- 
nected with  them  precedes  them  in  consciousness.  This 
recall  is  subject  to  the  same  laws  of  selection  that  are 
exhibited  in  attention.  When  these  dispositions  become 
realised,  they  constitute  the  elements  of  memory,  imag- 
ination, .and  reason.  They  are  similar  to  the  original 
sensations,  although  much  poorer  in  the  number  of  dis- 


RETENTION   AND   ASSOCIATION  153 

tinguishable  qualities.  In  the  representation  of  objects, 
not  all  the  elements  of  the  original  object  are  present. 
One  sense  department  predominates  in  recall  to  the 
exclusion  of  others. 

The  three  general  principles  upon  which  all  explana- 
tion in  psychology  must  rest  have  now  been  outlined. 
The  first  is  that  all  our  knowledge  comes  originally  from 
sensation.  All  of  its  fundamental  qualities  are  determined 
by  the  character  of  the  sense-organs,  together  with  the 
nature  of  the  external  stimuli.  There  are  some  forty 
of  these  simplest  qualities.  These,  by  their  interaction 
and  combination,  give  rise  to  the  complexes  of  qualities 
that  are  found  in  the  concrete  objects  of  experience. 
The  second  principle  is  that  the  order  in  which  mental  pro- 
cesses of  any  sort  enter  consciousness  and  whether  any  pro- 
cess does  or  does  not  enter  consciousness,  depends  upon  the 
nature  of  the  individual  rather  than  upon  the  forces  in 
the  physical  world.  The  nature  of  the  individual  that 
determines  the  entrance  to  consciousness  is  itself  derived 
from  the  earlier  experience  and  heredity  of  the  individual. 
This  fact  of  selection  is  the  deciding  influence,  not  only 
in  perception,  but  also  in  recall,  and  in  the  voluntary 
control  of  action.  The  third  and  last  of  these  principles 
is  that  experiences  leave  a  disposition  in  the  nervous 
system  that  tends  to  the  reinstatement  of  that  experience 
on  suitable  occasion.  These  three  principles  recur  to- 
gether again  and  again  in  the  explanation  of  the  concrete 
mental  operation.  Together,  they  suffice  for  the  under- 
standing of  practically  all  mental  processes. 


154  ESSENTIALS   OF   PSYCHOLOGY 


EXERCISES 

1.  Trace  the  similarities  and  differences  between  an  after-image, 
a  memory  after-image  or  primary  memory,  and  a  memory  image. 
Look  at  a  bright  object  for  ten  seconds.     Close  the  eyes  and  de- 
scribe or  note  the  after-image.    Take  a  momentary  glance  at  the 
same  object  and  note  the  memory  image  of  the  object  that  is  ob- 
tained.    Compare  it  with  the  after-image  for  clearness  of  outline 
and  quality.     Recall  some  similar  object  that  was  seen  yesterday 
and  compare  it  in  every  respect  with  the  other  two.     How  are  the 
three  processes  related  nervously  ? 

2.  How  are  these  impressions  retained?     Can  you  see  any  rela- 
tion between  the  nervous  basis  of  the  retention  and  the  nervous 
basis  of  habit  ? 

3.  Let  your  mental  stream  flow  at  random  for  half  a  minute. 
Write  out  the  ideas  that  came  to  you  in  the  order  of  their  appear- 
ance.    Can  you  trace  the  order  to  earlier  connections  of  simultane- 
ity or  succession  ?    Are  there  instances  in  which  one  idea  dissolves 
into  another  ?    Classify  the  associations  in  accordance  with  the  text. 
Are  the  simple  or  the  complex  associations  more  frequent  ? 

4.  Speak  a  word  to  an  assistant  with  the  request  to  say  the  first 
word  that  comes  to  mind.     Repeat  for  twenty  words.     Note  the 
sorts  of  connections  as  in  the  preceding  exercise.     How  long  does  it 
take  to  complete  the  series  ?     Choose  a  series  of  words  that  have 
easy  opposites  and  ask  the  assistant  to  give  the  opposites.     Take 
the  time  as  before.     How  does  it  compare  with  that  obtained  for 
the  first  series?    How  often  does  the  assistant  think  of  a  wrong 
word  before  the  opposite  comes  ?    How  does  the  second  series  illus- 
trate control  of  association  or  recall  ? 

5.  Recall  the  last  public  lecture  that  you  attended.     Can  you  see 
the  speaker  ?    Can  you  hear  the  words  that  he  speaks  ?    .Can  you 
recall  in  any  way  the  peculiarities  of  his  voice  ?    How  ?     Can  you 
reproduce  the  pressure  of  the  programme  that  you  held  in  your  hands? 
the  strain  from  an  uncomfortable  position?    Do  you  have  dis- 
tinct memories  of  taste  and  smell  ?    Can  you  grade  the  clearness  of 
the  memories  from  the  different  senses  ? 


RETENTION   AND    ASSOCIATION  155 

6.  Do  you  project  your  memory  images  in  the  same  direction  as 
your  sense  impressions  ?  For  instance,  do  you  think  of  the  speaker 
in  the  preceding  exercise  as  in  front  of  you,  or  behind,  or  to  the 
right  ?  How  large  do  you  think  the  speaker  to  be  in  your  memory 
projection?  Do  the  objects  have  the  same  colour  and  the  same 
background  as  the  actual  sensations  ? 

REFERENCES 

ANGELL  :  Psychology,  ch.  vii. 

TITCHENER:  Text-book  of  Psychology,  pp.  374-401. 

PILLSBURY  :  Attention,  ch.  vii. 

JAMES  :  Principles  of  Psychology,  vol.  i,  ch.  xix. 

SEASHORE  :  Elementary  Experiments  in  Psychology,  ch.  ix. 


CHAPTER  Vn 
PERCEPTION 

So  far  we  have  been  dealing  with  isolated  principles  and 
laws  that  are  used  in  all  mental  action.  In  perception 
we  begin  to  discuss  concrete  mental  processes.  We 
perceive  things,  not  sensations  or  images,  although  in 
psychology  we  think  of  things  when  appreciated  as  being 
in  some  way  made  up  of  sensations  and  images.  In  the 
discussion  of  perception  we  must  see  how  the  laws  and 
elements  that  have  been  discussed  in  the  last  three  chap- 
ters combine  and  interact  in  the  attainment  of  a  knowl- 
edge of  the  real  world.  First  we  must  see  that  there  is 
a  real  problem  here.  We  have  become  so  familiar  with 
seeing  things  and  with  hearing  things  that  it  seems  now 
that  objects  in  some  way  walk  over  into  our  consciousness 
with  the  same  characteristics  that  they  have  in  the  out- 
side world.  As  with  any  operation  that  has  been  fre- 
quently repeated,  we  soon  come  to  overlook  the  various 
steps  in  the  procedure,  and  it  is  necessary  to  learn  in 
some  indirect  way  what  is  actually  done.  In  this  in- 
stance it  is  doubtful  if  the  individual  ever  knew  the 
methods  by  which  he  attains  a  knowledge  of  objects. 
That  his  assumption  that  objects  are  like  the  effects 
they  produce  on  the  sense-organ  is  erroneous,  a  simple 
examination  of  the  facts  of  perception  proves  conclu- 
sively. The  sensations  that  are  received  are  added  to 
156 


PERCEPTION  157 

or  changed  to  make  them  correspond  more  exactly  to 
what  from  our  different  earlier  experiences  we  know  they 
must  be.  One  always  corrects  the  shape  of  the  table  top 
as  it  appears  in  perspective.  The  angles  are  right  angles 
as  we  see  them,  although  the  image  must  have  acute  and 
obtuse  angles.  One  also  makes  an  allowance  for  distance 
in  the  size  of  an  object  that  is  seen.  The  same  object  is 
always  given  the  same  size  no  matter  how  far  away  it 
may  be,  while  the  image  on  the  retina  diminishes  con- 
stantly as  the  distance  increases.  Evidently  objects  do 
not  walk  over  into  consciousness  as  one  might  suppose, 
but  the  percept  is  reconstructed  according  to  certain 
laws.  The  problem  of  perception  is  to  determine  these 
laws. 

The  first  fact  we  meet  is  that  perceptions  always  in- 
volve centrally  aroused  s'ensations  or  memories,  as  well 
as  sensations.  In  feeling  a  rough  surface  in  the  dark, 
one  supplies  memories  of  the  sight  of  surfaces  that  have 
given  similar  tactual  sensations.  If  the  arm  is  moved 
with  the  eyes  closed,  one  ordinarily  pictures  from  memory 
the  different  positions  of  the  arms ;  one  does  not  feel  the 
sensations  from  the  arm  that  tell  of  the  motion.  Simi- 
larly, in  any  perception,  the  object  is  made  up  in  part  of 
memories  and  in  part  of  sensations.  In  perception 
through  any  sense  the  same  law  holds.  When  a  dog 
barks  at  a  distance,  the  dog  is  pictured  in  its  proper 
direction,  —  visual  memories  are  added  to  the  auditory 
sensations.  The  memory  additions  can  be  actually 
discriminated  under  certain  conditions.  In  Figure  20, 
taken  from  Jastrow,  one  can  actually  see  lines  that  are 
suggested  by  the  shadows  that  are  drawn.  They  are  a 


158  ESSENTIALS   OF   PSYCHOLOGY 

little  fainter  than  the  actual  lines,  but  are  unmistakable 
and  can  be  seen  even  under  conditions  most  favourable  for 
observation.  In  all  perceptions  there  are  similar  addi- 
tions from  memory,  although  they  are  not  always  so 
easily  distinguished. 

In  many  cases,  however,  the  object  that  is  seen  is  not 
supplied  by  any  one  memory,  but  from  a  number  of 
earlier  experiences.  Thus  no  one  has  ever  seen  the  table 
top  as  it  presents  itself  in  perception.  When  seen  from 
one  side  it  slants  in  one  direction,  seen  from  the  opposite 
side  it  slants  in  the  other  direction.  When  seen  from  in 

£DJTOR 

FIG.  20. —  (From  Jastrow :  'Fact  and  Fable  in  Psychology,'  Fig.  2.) 

front  the  sides  converge  toward  the  back,  and  even  when 
looked  at  from  a  point  directly  above  the  centre  of  the  top, 
the  sides  would  not  be  straight,  as  we  know  from  the  shape 
of  the  surface  of  the  retina  and  direct  observation  under 
suitable  conditions.  While  the  retinal  image  must  al- 
ways have  been  distorted  in  some  way,  the  object  as  we 
perceive  it  is  rectangular  and  the  edges  are  perfectly 
straight.  Obviously  factors  other  than  the  recall  of  some 
single  earlier  memory  must  have  been  effective  in  making 
the  sides  straight  and  the  angles  right  angles.  It  is  prob- 
able that  some  of  this  modification  of  memories  and  sen- 
sations is  due  to  the  results  of  trials  and  of  various  actions. 
One  has  found  that  the  table  will  fit  into  square  corners, 
and  that  if  one  is  to  make  a  table  that  has  the  appearance 
of  this,  the  ends  and  sides  must  be  straight  and  all  the 


PERCEPTION  159 

angles  right  angles.  All  the  uses  and  tests  that  have  been 
made  harmonise  with  the  assumption  that  the  table  top 
is  a  square,  and  as  a  result  of  all  of  these  experiences  one 
sees  it  square,  whatever  the  retinal  image  may  be.  The 
results  of  all  of  the  various  experiences  cooperate  in  giving 
the  object  that  is  seen  the  appearance  it  has.  To  put  it 
the  other  way,  the  object  that  is  seen  is  the  one  that  serves 
to  explain  the  different  earlier  experiences;  it  is  the  one 
that  harmonises  all  of  the  uses  and  observations  of  it  in 
the  past.  By  constant  trial  and  use,  a  construction  de- 
velops that  proves  true  when  tested  in  any  way.  This  is 
accepted  as  the  real  object  as  opposed  to  mere  sensations. 
Whenever  the  sensation  presents  itself,  this  developed 
object  arises  in  consciousness. 

Not  only  do  constructions  that  have  proved  true  on 
test  replace  the  actual  sensations  that  are  true  under  only 
one  condition  of  perception,  but  sensations  that  on  test 
prove  not  to  have  external  existence  are  overlooked  al- 
together. Probably  many  readers  of  this  book  never  saw 
an  after-image  until  they  read  the  chapter  on  sensation, 
although  every  visual  sensation  has  its  after-image. 
Again  there  are  in  the  retina  blood-vessels  that  cast  a 
shadow  upon  the  sensitive  surface,  but  they  are  not  seen 
ordinarily.  If  a  candle  is  brought  to  one  side  of  the  eye 
and  moved,  the  network  of  vessels  will  be  evident. 
These  shadows  are  overlooked  because  they  have  no 
meaning  in  the  world  without.  In  general,  perception 
is  always  of  real  objects ;  sensations  that  do  not  corre- 
spond to  real  objects  are  always  neglected.  The  char- 
acter of  the  percept  is  changed  to  correspond  to  what  has 
proved  to  be  the  real  object.  An  object  in  its  turn  is  real 


1 60  ESSENTIALS   OF   PSYCHOLOGY 

if  it  will  stand  the  ordinary  tests,  will  satisfy  the  different 
uses  to  which  it  may  be  put,  and  will  harmonise  with  all 
the  different  experiences  that  are  related  to  it.  What  one 
sees  is  the  object  that  has  proved  itself  real  as  a  result  of 
the  various  earlier  perceptions  and  actions  that  have  been 
called  out  by  the  object.  Perception  is  different  from 
sensation  in  three  ways:  (i)  Memory  images  are  always 
added  to  the  sensations  to  complete  them  and  interpret 
them.  (2)  The  percept  is  not  a  mere  sum  of  sensations 
and  memories  but  an  explanation  of  this  and  earlier  ex- 
periences of  the  same  or  similar  objects,  developed  by 
repeated  experiences  and  tests  of  different  kinds.  This 
explanation  or  interpretation  is  frequently  very  little 
like  any  single  group  of  sensations  that  has  ever  been  re- 
ceived from  the  object.  (3)  Since  the  perception  satis- 
fies the  different  uses  to  which  it  has  been  put,  it  is 
regarded  as  real,  while  the  actual  sensations  may  be 
regarded  as  unreal  or  illusory. 

The  Determinants  of  Perception.  —  If  perception  is 
made  up  of  memories  as  well  as  of  sensations,  it  is  evident 
that  the  object  seen  depends  not  only  upon  the  sensations 
that  affect  the  sense-organ,  but  also  upon  the  memories 
that  one  possesses  and  the  laws  of  association  and  recall. 
Where  the  right  memories  are  lacking,  there  is  no  pos- 
sibility of  correct  or  complete  perception.  This  is  seen 
in  the  failure  to  understand  or  even  to  hear  all  that  is 
said  in  a  foreign  tongue.  One  could  not  repeat  accu- 
rately even  a  short  sentence  in  French  if  entirely  un- 
familiar with  the  language,  and  this  largely  because  the 
sounds  would  not  be  correctly  supplemented.  One  sees 
much  more  in  an  instrument  that  one  already  knows 


PERCEPTION 


161 


something  about.  To  go  back  to  the  beginning,  it  is 
probable  that  the  child  sees  practically  nothing  in  the 
world  because  it  has 
nothing  to  bring  to 
it  in  the  way  of  ear- 
lier experiences.  But 
as  in  the  case  of  re- 
call in  general,  what 
is  seen  depends  not 
only  upon  having 
the  memories,  but  Fl<>-  21. 

upon  being  able  to  get  them  back  at  the  right  time.  There 
is  frequently  a  choice  in  the  interpretation  that  shall 
be  put  upon  an  object.  Under  these  circumstances  what 
is  seen  depends  upon  the  setting  of  the  object  or  the 
attitude  at  the  moment.  Associations  are  subject  to  the 
same  laws  in  perception  as  in  recall  in  general.  The 
drawing  in  Figure  21  may  be  seen,  either  as  a  flight  of 
steps  or  as  a  cornice,  according  as  one  brings  the  right 
ideas  to  bear.  The  figure  from  Jastrow,  Fig.  22,  maybe 
seen  as  a  rabbit's  head  or  as  a  duck's  according  as  one 
thinks  of  one  or  the  other.  The  same  dependence  upon 
attitude  may  be  seen  in  more  usual  perceptions.  If  one  is 
listening  for  footsteps  at  night,  any  sound  is  likely  to  be 
interpreted  as  footsteps.  Asa  preliminary  statement  it 
may  be  asserted  that  any  perception  depends  upon 

(1)  the  presence  of  a  sensation  or  group  of  sensations ; 

(2)  that  these  sensations  recall   earlier  groups  of  sensa- 
tions or  objects;   and  (3)  which  one  of   several  objects 
or  interpretations  shall  be  suggested  depends  upon  the 
laws  of  association  and  the  laws  of   the   control  of  as- 


1 62  ESSENTIALS   OF  PSYCHOLOGY 

sociation  as  they  were  developed  in  the  preceding  chap- 
ter. We  may  proceed  to  the  discussion  of  the  way  these 
kws  act  in  giving  rise  to  the  different  sorts  of  percep- 
tion that  are  ordinarily  recognised. 

Perception  of  Space.  —  Two  properties  or  aspects  of 
objects  are  sufficiently  alike   for  all  to  be  treated  irre- 


FIG.  22. —  (From  Jastrow,  op.  cit.,  Fig.  19,  p.  295.) 

spective  of  the  objects  themselves.  These  are  space  and 
time.  Space  has  been  particularly  thoroughly  investi- 
gated. Following  the  usage  of  geometry,  psychology 
distinguishes  three  phases  of  the  perception  of  space; 
the  perception  of  position,  the  perception  of  distance  on 
the  surface  of  the  sense-organ,  and  perception  of  distance 
away  from  the  sense-organ.  Each  of  these  illustrates  the 
general  laws  of  perception.  The  perception  of  position 


PERCEPTION  163 

on  skin  or  eye  is  so  simple  and  has  been  made  so  frequently 
that  it  is  difficult  to  distinguish,  directly  or  indirectly, 
the  immediate  conditions  that  give  rise  to  it.  If  one 
touches  a  finger  or  the  cheek,  one  knows  at  once  what 
the  point  is  that  has  been  touched,  but  one  cannot  say 
how  it  is  known  that  it  is  that  point  and  no  other.  To 
bring  this  fact  under  our  explanation  of  perception,  it 
is  necessary  to  find,  first,  some  old  experiences  that  were 
suggested  when  the  point  was  touched,  and  second, 
the  peculiar  quality  of  the  point  that  suggests  them. 
Various  theories  have  been  held  concerning  the  nature  of 
both.  One  of  the  oldest  is  that  there  is  a  sign  of  position, 
the  '  local  sign,'  that  is  different  for  each  point  touched 
and  for  each  point  of  the  retina  stimulated,  and  that  this 
'  local  sign '  suggests  the  position.  No  one  has  accu- 
rately described  the  '  local  sign/  however,  and  one  cannot 
discover  it  when  one  seeks  it.  Another  theory  is  that 
stimulation  of  each  point  on  the  skin  tends  to  call  out 
some  reflex  movement  and  that  this  reflex  is  different  for 
each  point.  There  is,  on  this  theory,  either  a  movement 
or  a  tendency  to  movement  which  is  different  for  each 
point  of  the  skin  or  eye.  This  theory  is  partly  satis- 
factory ;  the  main  objection  is  that  one  can  recognise 
position  more  accurately  than  one  can  touch  points  on 
the  skin,  and  that  the  eye  is  constantly  moving  over  dis- 
tances that  are  larger  than  the  least  appreciable  differ- 
ences in  position.  Another  suggestion  for  the  perception 
of  position  on  the  skin  is  that  the  contact  recalls  a  visual 
picture  of  the  point.  This  is  the  only  suggestion  that  can 
be  confirmed  by  actual  observation.  The  most  that  can 
be  said  is  that  perception  of  position  is  due  to  some  pe- 


164  ESSENTIALS   OF   PSYCHOLOGY 

culiar  quality  or  motor  connection  that  each  point  on  the 
skin  or  retina  possesses.  It  is  likely  that  position  itself 
is  an  idea  so  frequently  used  that  its  nature  has  become 
very  complex,  and  the  elements  are  no  longer  analysed 
from  the  mass.  It  is  made  up  partly  of  movements  or 
tendencies  to  movement  and  partly  of  ideas  derived 
from  sight  or  touch  as  the  case  may  be,  but  probably  a 
number  of  other  elements  are  also  involved  in  it.  This 
notion  of  position,  whatever  its  nature,  explains  all  the 
various  experiences  and  responds  satisfactorily  to  all 
tests.  With  use,  the  completed  notion  has  come  to  re- 
place the  different  elements  so  entirely  that  they  are  lost 
in  it,  and  cannot  now  be  analysed  from  it.  The  stimu- 
lation of  any  point  on  skin  or  retina  calls  out  the  corre- 
sponding notion  of  position,  and  that  is  all  that  can  be 
said  with  certainty. 

The  perception  of  distance  on  the  surface  of  skin  or 
retina  is  dependent  upon  the  suggestion  of  a  similar 
complex  that  has  been  no  more  completely  analysed. 
The  one  element  that  has  been  discovered  in  the  notion  of 
distance  is  movement.  Several  illusions  indicate  that 
one  appreciates  distance  on  the  retina  by  moving  the  eyes 
from  point  to  point.  Thus,  vertical  distances  are  over- 
estimated as  compared  with  horizontal  distances,  be- 
cause the  adjustment  of  the  eye  muscles  makes  vertical 
movements  of  the  eyes  more  difficult  than  horizontal 
ones.  Distances  on  the  skin  also  tend  to  be  translated 
into  movement,  and  the  mistakes  that  are  made  show 
dependence  upon  movement.  In  addition,  it  is  probable 
that  the  distances  on  the  skin  are  translated  into  visual 
distance  for  interpretation,  and  that  visual  distances 


PERCEPTION  165 

may  more  rarely  be  translated  into  distances  on  the  skin. 
Visual  distances  are  certainly  influenced  by  the  length 
of  movements  of  arm  and  hand.  That  there  is  usually 
reference  from  one  sense  to  another  is  shown  by  the  fact 
that  where  two  systems  of  distance  are  independent  and 
not  corrected  by  comparison,  large  mistakes  are  apt  to 
be  made.  This  explains  the  large  size  that  cavities  in  the 
teeth  seem  to  have  when  felt  by  the  tongue,  as  compared 
with  their  size  when  seen  in  the  dentist's  mirror.  Space 
as  perceived  by  the  tongue  is  seldom  corrected  by  visual 
space,  while  other  tactual  distances  are  constantly  sub- 
ject to  that  correction.  Distance,  then,  is  a  complex  of 
numerous  factors  that  have  been  lost  in  a  more  general 
notion.  This  notion  is  aroused  whenever  one  estimates 
distance  by  the  eye,  on  the  skin,  or  by  the  movement  of 
the  members.  What  it  is  in  itself  one  can  no  longer  say, 
if  one  ever  was  able  to  analyse  all  of  the  experiences  that 
have  gone  to  make  it  up  or  that  have  served  to  develop  it. 
Perception  of  the  Third  Dimension.  —  The  perception 
of  the  distance  of  objects  from  the  eye  illustrates  all  of 
the  laws  of  perception  even  more  clearly  than  the  simpler 
forms  of  space  perception.  The  striking  fact  in  connec- 
tion with  perception  of  this  third  dimension  is  that,  while 
the  rays  of  light  affect  the  retina  only,  the  objects  that 
reflect  them,  all  seem  to  be  some  distance  away  from  the 
eye.  Evidently  distance  cannot  depend  upon  how  the 
retina  is  stimulated,  because  a  point  of  light  affects  the 
retina  in  the  same  way  whether  the  source  be  two  feet 
away  or  as  remote  as  a  fixed  star.  That  the  actual  dis- 
tance makes  little  or  no  difference  can  also  be  demon- 
strated by  the  fact  that  objects  within  the  eye  and  even 


1 66  ESSENTIALS   OF   PSYCHOLOGY 

within  the  retina  seem,  when  seen  at  all,  to  be  in  the  outer 
world  and  at  a  distance  from  the  eye  that  depends  upon 
the  adjustment  of  the  eyes  at  the  time.  So,  if  one  will 
lie  upon  the  back  on  a  summer  day,  one  will  notice  little 
bright  specks  floating  over  the  sky.  These  are  really  the 
blood  corpuscles  darting  through  the  blood-vessels  in  the 
retina,  but  when  the  eye  is  fixed  upon  the  sky  they  are 
apparently  very  remote.  The  problem  of  the  perception 
of  distance  is  one  of  determining  what  in  the  character  of 
the  excitation  calls  out  the  idea  of  distance,  and  what  the 
nature  of  that  idea  is. 

The  factors  that  serve  to  suggest  the  distance  have 
been  pretty  fully  made  out.  They  may  be  classified 
into  eight  groups,  three  physiological  and  five  psycho- 
logical. The  physiological  factors  are  related  directly  to 
the  adjustment  of  the  eyes.  With  one  eye  only,  the  most 
important  element  is  the  chajige  intheadjustment  of  the 
ciliary  muscle  that  focusses  the  eye  for  different  distances. 
If  one  looks  at  a  distant  object,  the  lens  is  flat  and  the 
muscle  of  accommodation  is  relaxed;  if  one  looks  at  a  near 
object,  the  lens  is  rounded  and  the  muscle  contracted. 
One  may  feel  the  strain  as  one  looks  at  a  near  object. 
One  may  see  the  effects  of  the  thickening  of  the  lens,  if 
one  will  look  across  the  cornea  of  the  eye  of  another  when 
he  looks  first  at  a  near,  then  at  a  distant,  object.  When 
he  looks  at  a  near  object,  the  iris  is  seen  to  protrude  into 
the  cornea ;  when  he  looks  at  a  distant  object,  but  little  of 
the  iris  can  be  seen..  The  strain  of  accommodation  gives 
an  idea  of  the  distance  of  the  object.  Slight  strain  means 
distance,  increased  strain  means  nearness.  The  esti- 
mation of  distance  by  one  eye  is  much  less  accurate  than 


PERCEPTION  167 

with  two  eyes,  as  can  be  shown  by  asking  one  to  put 
his  finger  through  a  ring  held  sidewise.  With  one  eye 
large  mistakes  will  be  made,  while  with  two  eyes  one  can 
put  the  finger  through  each  time.  Muscular  strain  is  also 
a  factor  in  binocular  perception  of  distance.  This  is  the 
strain  on  the  muscles  as  the  eyes  converge  upon  a  point. 
When  one  looks  at  a  distant  object,  the  eyes  are  parallel ; 
as  one  looks  at  nearer  objects,  the  eyes  converge,  and  the 
nearer  the  object,  the  greater  the  convergence.  This 
can  be  seen  directly  in  another's  eyes.  When  he  looks 
at  a  distant  object,  the  white  shows  about  equally  on 
each  side ;  as  he  looks  at  an  object  only  a  foot  away, 
considerably  more  white  will  show  on  the  outside  than  on 
the  inside  of  the  eyes.  This  adjustment  is  made  known 
to  the  observer  by  the  strain  sensations  that  vary  with 
the  distance.  It  is  to  be  emphasised  that  none  of  these 
strain  sensations  are  noticed  for  themselves.  They  are 
overlooked  in  the  interpreting,  and  one  appreciates  the 
distance  alone,  not  the  strains  that  suggest  it. 

One  of  the  most  important  elements  in  the  perception 
of  distance  is  the  fact  that  an  object  when  near  at  hand 
is  seen  differently  witheach  eye^  If  one  will  hold  any 
object  before"tne~eye  ancTTbok  at  it  first  with  one  eye,  then 
with  the  other,  it  will  be  noticed  that  one  eye  sees  more 
of  one  side,  the  other  more  of  the  other.  If  both  eyes  are 
opened,  it  is  possible  to  distinguish  in  the  common  view 
the  contributions  of  each  eye.  The  difference  in  the  pic- 
tures decreases  as  the  objects  move  farther  away.  The 
distance  of  the  object  is  estimated  by  the  amount  of 
difference  in  the  impressions  on  the  two  retinas.  Objects 
that  are  not  looked  at  directly  are  all  seen  double.  If 


1 68  ESSENTIALS   OF   PSYCHOLOGY 

one  will  hold  two  pencils  at  different  distances  from  the 
eyes,  it  will  be  noticed  that  the  pencil  not  fixated  is 
double,  whether  it  be  nearer  or  farther  from  the  eye. 
The  distance  of  these  objects  is  estimated  directly  in 
terms  of  the  degree  of  doubleness  of  the  images.  As  a 
result  of  these  double  images,  every  object  in  the  field  of 
vision  gives  an  immediate  sign  of  its  distance.  It  is 
largely  due  to  these  double  images  that  the  whole  field 
of  vision  is  seen  at  any  moment  to  have  depth.  The 
stereoscope  makes  application  of  this  principle  of  double 
images  to  give  the  appearance  of  depth  to  pictures. 
The  stereoscope  slide  has  two  photographs  taken  from 
slightly  different  positions.  When  the  two  pictures  are 
combined,  the  result  is  a  series  of  double  images  that 
are  similar  to  those  that  would  have  been  produced  had 
the  observer  been  standing  where  the  photographs  were 
taken.  The  difference  in  the  pictures  may  be  seen  if  one 
will  compare  the  position  of  the  same  object  in  each.  An 
object  in  the  foreground  will  be  seen  nearer  the  right  edge 
of  the  view  in  the  left  picture,  and  farther  from  it  in  the 
right  picture;  in  the  background,  the  relation  is  reversed. 
These  double  images  again  are  not  noticed  for  themselves, 
either  in  perceiving  actual  distances  or  in  the  stereoscope. 
They  are  overlooked  in  favour  of  the  distances  that  they 
suggest. 

The  psychological  signs  of  distance  are  found  in  certain 
qualities  of  images  which  vary  with  the  distance  of  their 
objects.  The  most  important  of  these  is  the  variation  in 
size_of  the  retinal  image  of  objects  as  they  change  their 
distance.  This  is  the  element  that  the  painter  makes  use 
of  in  perspective  drawing.  He  draws  the  more  distant 


PERCEPTION  169 

objects  smaller  than  the  nearer,  and  we  interpret  that  to 
mean  that  they  are  distant.  A  second  sign  of  distance 
is  the  haze  and  changed  colour  that  come  with  distance. 
Distant  objects  are  hazy,  indistinct,  and  blue  in  colour, 
while  near  objects  are  clear  and  have  their  own  colours. 
The  changed  colour  and  haze  depend  upon  the  amount 
of  air  intervening.  In  a  very  clear,  dry  air,  estimates  of 
distance  are  subject  to  large  mistakes  on  the  part  of  one 
who  comes  from  a  lower  altitude  and  denser  atmosphere. 
Distant  objects  show  but  little  haze  or  change  of  colour, 
and  in  consequence  are  regarded  as  much  nearer  than 
they  actually  are.  A  third  factor  of  some  importance  in 
giving  an  idea  of  the  distance  of  objects  is  their  rate_^f 
movement,  either  when  they  themselves  move  or  when 
the  head  or  body  of  the  observer  is  moved.  If  the  usual 
rate  of  motion  of  an  object  is  known,  its  apparent  rate 
indicates  its  distance.  Distant  objects  seem  to  move 
more  slowly,  near  ones  more  rapidly.  A  distant  railway 
train  seems  to  crawl  across  the  landscape,  while  the  near 
one  rushes  past.  As  one  moves  the  head  with  the  eyes 
fixed  upon  the  horizon,  near  objects  are  displaced  con- 
siderably, distant  ones  very  slightly  or  not  at  all.  If  one 
is  looking  at  a  near  object  and  moves  the  head,  objects 
far  from  the  point  of  fixation  move  more,  those  near  it 
less.  One  may  measure  the  distance  of  the  object  by  the 
rate  of  motion.  A  fourth,  very  simple  sign  of  relative 
distance  is  superposition.  Objects  that  hide  parts  of 
other  objects  are  evidently  nearer  than  the  objects 
covered.  Finally,  shadows  furnish  a  means  of  estimating 
the  relative  distance  of  parts  of  the  same  object.  Bright 
parts  of  the  surface  are  ordinarily  nearer,  shaded  parts 


1 70  ESSENTIALS   OF   PSYCHOLOGY 

more  distant.  The  interpretation  depends  largely  upon 
the  way  the  light  is  falling,  but  with  any  illumination 
lights  and  shadows  give  a  means  of  estimating  the  dis- 
tance of  the  parts.  These  five  characteristics  of  the 
retinal  image  combine  with  the  three  factors  mentioned 
above  to  give  our  notion  of  the  distance  of  objects  that 
excite  the  retina.  The  idea  of  distance  that  is  suggested 
depends  upon  all  taken  together. 

If  the  suggestion  for  the  distance  is  found  in  one  or 
more  of  these  factors,  the  question  at  once  arises  what  the 
idea  of  distance  is  that  they  suggest.  One  of  the  early 
theories  and  one  that  still  has  many  advocates  is  that  the 
various  signs  of  distance  serve  to  recall  memories  of  move- 
ments that  were  necessary  to  reach  the  object.  Move- 
ment, no  doubt,  contributes  a  large  share  to  the  general 
idea.  It  is  as  certain  that  there  are  other  elements  that 
enter.  Estimates  in  terms  of  movement  alone  are  more 
inaccurate  than  those  in  terms  of  vision  alone.  One,  for 
example,  has  no  accurate  idea  of  the  distance  walked 
through  in  the  dark,  and  walking  in  the  dark,  one  fre- 
quently tries  to  think  how  great  the  distance  would  look. 
Certainly  the  visual  estimate  of  a  distance  is  ordinarily 
more  accurate  than  the  estimate  of  distances  traversed 
in  the  dark.  It  is  probable  that  the  idea  of  distance  is 
complex,  made  up  of  a  great  many  experiences  of  dis- 
tance. In  this,  it  is  like  the  idea  of  position  or  of  distance 
on  the  surface  of  the  sense-organ.  What  elements  have 
contributed  to  the  total  effect  cannot  now  be  determined 
accurately.  But  to  movement  must  be  added  the  ap- 
pearance of  the  distances,  when  viewed  from  the  side  and 
from  other  angles,  and  all  the  various  activities  that  are 


PERCEPTION  171 

furthered  and  hindered  by  distance.  Whatever  this 
complex  idea  may  be,  it  is  at  once  suggested  by  the  strain 
sensations,  by  double  images,  and  the  various  character- 
istics of  the  image  that  constitute  the  psychological  signs 
of  distance.  Each  of  these  primary  space  ideas  has 
special  stimuli  that  suggest  it,  and  is  itself  a  complex 
idea  that  is  like  no  single  experience,  but  is  derived  from 
and  explains  many  experiences.  Space,  as  a  whole,  is 
only  another  general  idea  of  the  same  kind  and  origin 
that  unites  and  explains  the  several  less  general  spatial 
ideas  and  which  is  related  to  each  of  them,  or  combined 
from  them. 

Perception  of  Motion.  —  A  second  form  of  perception 
that  is  related  to  the  perception  of  space  and  is  also 
common  to  all  objects  is  the  perception  of  motion,  par- 
ticularly perception  of  motion  by  the  eye.  We  may 
distinguish  two  ways  of  recognising  motion.  In  one,  we 
know  merely  that  an  object  has  moved ;  in  the  other,  the 
object  is  seen  to  move.  The  difference  is  shown  by  the 
second  hand  and  minute  hand  of  the  watch ;  one  can  be 
seen  to  move,  the  other  we  know  to  move  only  because  it 
changes  its  position  between  observations.  The  former 
alone  requires  explanation.  Apparently  perception  of 
motion  depends  upon  the  after-images  that  are  left  on 
the  retina  by  the  moving  object.  If  the  hand  is  moved 
across  the  field  of  vision,  it  will  be  noticed  that  there  is  a 
streak  behind  it  that  persists  for  a  brief  time.  The 
motion  is  perceived  on  the  basis  of  this  image.  The  di- 
rection of  the  motion  can  be  determined  by  the  fact  that 
the  image  is  most  clear  near  where  the  object  was  last 
seen.  Motion  of  the  eye  shows  itself  by  after-images  of 


172  ESSENTIALS   OF   PSYCHOLOGY 

all  stationary  objects.  Where  both  eye  and  object  are 
in  motion,  the  motion  of  each  must  be  inferred  from  the 
various  after  effects.  The  interpretation  in  each  case  is 
not  explicit.  As  in  most  perceptions,  the  result  alone  is 
evident;  the  occasion  for  the  perception  is  overlooked. 
In  many  cases  movement  is  ascribed  to  one  object  or 
another  on  the  basis  of  probability.  In  this  a  mistake  is 
often  made.  For  example,  when  one  is  sitting  in  a  car 
in  a  station  and  a  train  on  the  next  track  starts,  one  is 
very  likely  to  believe  that  one's  own  car  has  started. 
This  is  because  one  expects  the  car  to  start,  and  also 
because  one  is  unaccustomed  to  seeing  objects  so  large 
as  the  side  of  the  car  in  motion.  The  retinal  image  is 
ambiguous,  and  motion  is  ascribed  to  the  object  that  is 
regarded  as  most  likely  to  move. 

The  Perception  of  Space  by  the  Ears.  —  Two  problems 
must  be  considered  in  relation  to  the  auditory  perception 
of  space,  the  appreciation  of  the  distance  from  which  the 
sound  comes,  and  its  direction.  In  both  cases  the  ref- 
erence is  to  sight.  When  one  hears  a  sound,  one  at  once 
gives  it  a  place  in  the  visual  field.  The  problem  in  each 
case  is  to  determine  the  characteristics  of  the  sound  that 
suggest  one  distance  or  one  direction  rather  than  another. 
The  distance  to  which  a  sound  is  referred,  is  determined 
very  largely  by  the  intensity  of  the  sound,  provided  the 
actual  intensity  is  known.  The  barking  of  a  dog  is  ap- 
preciated as  near  or  far  according  to  its  intensity  as  com- 
pared with  the  intensity  of  the  sound  when  the  dog  is 
barking  near  at  hand.  Allowance  is  made  for  the  bark  of 
different  sorts  of  dogs  on  the  basis  of  the  quality  of  the 
bark.  Where  the  nature  of  a  sound  is  misinterpreted, 


PERCEPTION  173 

the  distance  is  wrongly  estimated.  The  buzzing  of  a  fly 
very  near  is  occasionally  mistaken  for  some  strange,  loud 
noise  at  a  distance,  and  similar  mistakes  in  judging  dis- 
tances are  rather  frequent.  The  direction  of  the  sound 
seems  to  be  appreciated  by  the  difference  in  the  intensity 
or  quality  of  a  sound  as  it  affects  the  two  ears.  A  sound 
to  the  right  affects  the  right  ear  more  strongly,  a  sound 
to  the  left  stimulates  the  left  more  intensely.  The  rela- 
tive differences  serve  to  indicate  the  direction  of  the  sound. 
In  the  median  plane,  the  plane  midway  between  the  two 
ears,  the  effect  upon  both  ears  is  the  same,  and  in  conse- 
quence in  this  plane  it  is  very  difficult  to  say  where  a  tone 
is.  A  pure  tone  directly  in  front  may  be  referred  to  a 
point  directly  behind,  or  to  any  other  part  of  this  plane. 
While  the  different  intensity  of  the  tones  as  they  present 
themselves  to  the  two  ears  seems  to  be  the  important 
element  in  the  determination  of  the  direction  of  the  pure 
tones,  noises  and  complex  tones  apparently  undergo 
some  slight  change  in  their  quality  with  change  in  direc- 
tion, which  indicates  position.  This  change  in  quality 
is  due  to  factors  that  have  not  been  altogether  deter- 
mined, but  it  seems  probable  that  it  is  in  part  the  result 
of  the  reenforcement  of  different  components  of  the  com- 
plex as  the  sound  comes  to  the  ear  from  different  direc- 
tions. 

For  the  blind,  the  auditory  perception  of  space  is  much 
more  important  than  for  the  seeing  individual.  Not  only 
are  they  more  accurate  in  all  of  their  localisations  of 
sound,  but  they  use  sound  to  obtain  an  idea  of  the  space 
in  which  they  are  walking,  and  of  the  distance  of  ob- 
stacles. The  echo  of  the  footsteps  is  different  in  different 


174          ESSENTIALS  OF  PSYCHOLOGY 

sorts  of  rooms,  and  the  time  between  the  echo  and  the 
original  sound  increases  with  the  distance  of  a  wall  or 
other  obstacle.  Even  when  the  echo  is  not  noticed,  it 
affects  the  quality  of  the  tone.  The  blind  have  learned 
to  connect  this  quality,  of  the  tone  with  the  different 
distances  of  objects,  and  guide  their  movements  accord- 
ingly. When  the  boys  in  a  blind  asylum  were  provided 
with  felt  slippers  in  place  of  their  heavy-soled  shoes,  it 
was  found  that  they  could  no  longer  avoid  obstacles 
with  their  usual  skill.  The  footsteps  were  noiseless,  and 
they  were  deprived  of  their  most  important  means  of 
appreciating  objects  at  a  distance.  It  is  said  that  the 
blind  ordinarily  refer  their  larger  spaces  to  auditory 
qualities  as  we  refer  them  to  vision.  In  all  respects  per- 
ception of  space  by  the  ear  follows  the  same  law  as  per- 
ception by  the  eye  or  skin. 

Perception  of  Time.  —  Much  less  is  known  definitely 
of  the  perception  of  time  than  of  the  perception  of  space. 
Time  is  a  much  simpler  idea  than  the  space  idea,  and  has 
fewer  components.  The  statement  is  often  made  that 
time  has  but  one  dimension,  while  space  has  three.  The 
idea  of  time  reduces  to  before  and  after,  together  with  the 
notion  of  different  points  in  the  past.  The  most  essen- 
tial part  of  the  idea  is  change,  and  the  occasion  for  the 
appreciation  of  time  is  also  change  of  some  sort.  Rhyth- 
mic changes  in  nature,  the  movements  of  the  heavenly 
bodies  or  of  pendulums,  give  the  scientific  means  for  the 
measurement  of  time.  Psychological  theories  look  to 
changes  in  the  body  for  the  explanation  of  our  apprecia- 
tion of  time.  Two  sorts  of  time  must  be  distinguished. 
The  one  applies  to  intervals  of  less  than  four  seconds  in 


PERCEPTION  175 

length,  the  other  to  longer  periods  of  time.  Shorter 
periods  ordinarily  are  referred  to  changes  in  strains,  par- 
ticularly the  strain  that  accompanies  expectation,  and  to 
rhythmic  vital  processes  such  as  breathing.  One  com- 
pares short  periods  of  time  on  the  basis  of  the  relative 
strains  of  expectation.  The  strains  commence  at  the 
beginning  of  the  first  interval  and  increase  in  intensity 
until  the  end.  They  begin  again  with  the  second  inter- 
val, and  when  they  have  reached  the  same  intensity  as 
at  the  end  of  the  first  interval,  it  is  said  that  the  second 
interval  is  equal  to  the  first.  These  periods  of  expecta- 
tion do  not  ordinarily  last  more  than  three  or  four  seconds 
without  relaxation,  and  even  at  three  seconds  become  very 
unpleasant.  This  is  evident  to  anyone  who  has  watched 
the  movement  of  a  clock  with  a  slow  torsion  pendulum  or 
any  similar  slow  rhythmic  movement.  The  strain  of  wait- 
ing for  the  turn  becomes  unendurable  after  a  short  period. 
Periods  longer  than  three  or  four  seconds  are  estimated 
in  terms  of  the  events  that  fill  them.  Periods  in  which 
much  happens  seem  long,  while  periods  which  have  few 
incidents  or  are  filled  with  the  monotony  of  routine  acts 
seem  short.  A  month  of  the  ordinary  life  seems  no  longer 
than  a  week  of  travel.  This  law  of  dependence  upon  the 
number  of  events,  holds  primarily  of  time  when  considered 
in  retrospect.  When  the  time  is  passing,  the  greater  the 
number  of  events,  the  shorter  seems  the  time;  while 
empty  time  seems  very  long.  The  difference  probably 
depends  upon  the  different  ways  of  measuring  time. 
While  one  is  merely  waiting  or  is  bored,  one  is  constantly 
aware  of  the  strain  sensations  that  accompany  expecta- 
tion. In  other  words,  empty  time  seems  long  as  one  lives 


1 76  ESSENTIALS   OF   PSYCHOLOGY 

it  through,  but  when  one  looks  back  upon  it  afterward, 
no  events  stand  out  and  the  time  appears  short.  Time 
filled  with  the  ordinary  routine  seems  short  both  in  pass- 
ing and  retrospect.  One  is  too  much  interested  to  notice 
the  strains  that  mark  the  passage  of  time  or  else  the 
strains  do  not  get  a  chance  to  reach  any  marked  intensity, 
because  events  succeed  each  other  so  closely,  and  there  is 
nothing  noteworthy  enough  to  be  prominent  in  memory. 
The  apparent  decrease  in  the  length  of  the  years  with 
increasing  age  is  an  expression  of  this  law.  In  early  life, 
every  event  is  new  and  seems  important;  as  one  grows 
older,  less  and  less  attention  is  given  to  the  routine  of  life, 
and  in  consequence  the  days  and  weeks  seem  less  full. 
Perception  of  time,  then,  is  due  to  a  suggestion  from 
strain  sensations  or  from  the  events  that  have  filled  a 
given  interval.  The  idea  that  is  suggested  is  a  complex 
of  experiences,  based  primarily  upon  change,  but  involv- 
ing many  experiences  of  motion,  and  even  of  space,  that 
have  combined  with  them  in  a  consistent,  unitary  whole. 
So  far  as  the  idea  can  be  analysed,  it  is  on  the  same  level 
as  the  idea  of  space. 

Reading  as  an  Illustration  of  Perception.  —  The  per- 
ception of  particular  objects  illustrates  the  same  three 
laws  as  these  more  general  characteristics  of  all  objects. 
One  of  the  best  illustrations  of  the  perception  of  par- 
ticular things  is  to  be  found  in  reading.  As  in  most 
forms  of  perception,  reading  seems  to  be  a  process  of 
taking  words  directly  from  the  page  to  consciousness. 
Investigation  of  the  reading  process  under  various  con- 
ditions has  demonstrated,  however,  that  one  does  not 
actually  see  all  the  letters  or  words  that  are  read,  but  that. 


PERCEPTION  177 

one  receives  suggestions  only  of  the  words,  and  con- 
structs or  recalls  them  on  the  basis  of  these  suggestions. 
In  the  ordinary  connected  reading,  it  has  been  shown 
that  one  does  not  read  by  running  the  eye  slowly  and 
regularly  across  the  line,  as  is  usually  supposed,  but  that 
reading  is  by  a  series  of  snap-shots  of  the  line.  The  eye 
moves  by  jumps  and  all  reading  is  done  during -a  few 
pauses.  The  number  of  these  pauses  is  greater  with 
less  familiar  material  than  with  more  familiar;  there 
will  be  from  three  to  six  or  more  in  the  average  length  of 
line.  The  amount  of  material  that  is  read  at  each  pause 
is  greater  than  can  be  attended  to  at  a  single  glance.  One 
must  supply  the  rest.  That  misprints  are  frequently 
overlooked  is  also  an  indication  that  one  receives  but 
little  from  the  page,  and  adds  much  from  memory. 

Three  forms  of  reading  may  be  distinguished ;  these 
differ  in  the  sensations  that  suggest  the  matter  read, 
and  in  the  material  that  is  brought  out  to  supplement 
the  sensations.  In  one  we  read  letters ;  in  the  second 
we  read  words ;  and  in  the  third  we  read  for  sense,  and 
neglect  both  letters  and  words.  These  three  are  fre- 
quently combined  or  mixed  in  practice.  When  reading 
the  letters,  as  in  proof-reading,  or  in  reading  separate 
words,  one  usually  sees  only  part  of  the  word,  and  fills 
out  by  associates  the  letters  seen.  Thus  if  '  t '  is  seen, 
one  tends  to  supplement  by  '  h,'  and  '  1 '  is  supplemented 
by  '  y,'  or  other  frequent  associates,  but  these  associates 
will  depend  upon  the  environment  or  setting  of  the 
letter.  If  the  letter  '  1'  is  near  the  end  of  the  word,  it 
will  be  supplemented  by  *  y,'  while  some  other  supple- 
ment would  be  more  likely  at  the  beginning.  The  other 


178          ESSENTIALS  OF  PSYCHOLOGY 

letters  that  have  been  read  will  also  play  a  part.  Often, 
too,  the  word  is  read  from  its  general  form,  and  the 
letters  that  are  known  to  compose  the  word  are  supplied 
later.  Even  more  general  contexts  will  have  a  part  in 
the  process.  If  one  is  reading  German  words,  one  sort 
of  associates  will  predominate;  if  French,  another 
sort.  In  addition  to  this,  one  may  at  a  second  glance 
look  to  see  if  the  letter  suspected  is  actually  present,  and 
in  the  right  place.  Even  in  reading  for  letters,  associa- 
tion processes  play  a  considerable  part;  the  operation 
is  not  one  of  sensation  alone. 

The  associative  processes  have  a  more  important  role 
in  reading  words,  whether  in  connected  discourse  or 
singly.  Here,  what  is  seen  clearly  is  the  form  of  the 
word  with  a  few  letters,  and  these  serve  to  call  up  the 
whole  word.  That  one  usually  reads  words  rather  than 
series  of  letters  is  indicated  by  the  fact  that  one  can 
read  short  words  more  quickly  than  single  letters.  The 
word  form,  with  or  without  the  initial  letters,  suggests 
the  word  by  the  laws  of  association,  but  the  associates 
are  controlled  by  the  context  and  setting.  A  form  that 
in  one  connection  suggests  '  there  '  will  in  another  set- 
ting suggest  '  these '  just  as  certainly  and  quickly. 
One  selects  the  word  that  makes  sense  in  the  particular 
context,  and,  if  one  mistakes  the  context,  may  supply  a 
word  that  is  not  present,  or  change  the  word  that  is 
seen  to  fit  the  context.  The  more  usual  form  of  read- 
ing, however,  is  neither  of  letters  nor  of  words,  but  of 
ideas.  As  one  reads  one  sees  with  the  mind's  eye  the 
scenes  that  the  author  describes;  the  words  are  over- 
looked or  neglected.  This  reading  for  sense  or  for 


PERCEPTION  179 

meaning  follows  the  same  laws  as  other  forms  of  reading. 
The  visual  impressions  have  been  connected  with  ideas, 
and  selection  is  made  from  the  ideas  in  accordance  with 
the  context,  with  what  has  been  read,  and  with  the  ex- 
pectation of  what  the  author  intends  to  say.  The  fact 
that  the  same  word  may  have  different  meanings  in 
different  contexts  without  any  interference  of  one  mean- 
ing with  the  other  is  an  illustration,  at  once  of  the 
dominance  of  the  idea,  and  of  the  importance  of  the 
context  in  selecting  the  idea.  '  Lead  '  is  a  verb  in  one 
context  and  a  noun  in  another,  but  one  never  thinks  of 
the  noun  when  the  verb  is  intended.  The  idea  that  is 
suggested  is  entirely  different  in  the  two  contexts,  and 
the  idea  alone  is  important.  It  is  because  one  is  so 
much  more  concerned  with  the  idea  than  with  the 
letters  or  words,  that  one  so  seldom  distinguishes  be- 
tween what  is  actually  received  from  sensation  in  read- 
ing and  what  is  added  to  interpret  the  sensations.  One 
is  concerned  to  know  what  the  author  is  saying,  not 
how  one  knows  it ;  the  ideas  are  appreciated,  not  the 
process  of  receiving  them. 

As  this  page  is  read,  the  eyes  dart  from  point  to  point 
on  each  line,  making  perhaps  five  pauses  to  take  in  the 
general  form  of  the  words  and  an  occasional  letter. 
These  sensations  suggest  familiar  words  or  familiar  ideas, 
and  the  suggestions  are  controlled  by  the  context  and 
the  appreciation  of  what  is  to  be  discussed.  As  the 
result,  you  construct  for  yourself  the  ideas  that  I  have 
in  mind  as  I  write.  You  are  aware  of  the  ideas;  it  is 
only  when  some  new  word  is  introduced,  or  the  state- 
ments are  not  clear,  that  you  become  aware  of  the 


180          ESSENTIALS  OF  PSYCHOLOGY 

words.  All  other  perceptions  follow  these  same  laws. 
In  listening  to  spoken  words,  you  appreciate  the  ideas, 
not  the  sounds.  Sometimes  when  one  is  listening  to  a 
language  that  is  more  familiar  in  print  than  in  speech, 
one  translates  the  sounds  into  visual  pictures  before  one 
understands,  just  as  in  the  early  stages  of  reading  one 
may  translate  the  words  seen  into  spoken  words  before 
they  are  understood.  In  both  instances  one  usually  trans- 
lates into  ideas  at  once.  Other  objects  are  perceived  in 
the  same  way  and  by  the  same  laws.  Any  object  gives 
a  few  sensations  that  correspond  to  the  letters  or  form 
of  the  words,  while  the  object  that  is  seen  corresponds 
to  the  words  or  to  the  ideas  that  are  read.  The  distinc- 
tion between  the  mere  sensations  and  the  appreciated 
object  cannot  always  be  made  out  so  clearly,  but  it  is 
altogether  probable  that  complete  analysis  would  dem- 
onstrate the  same  laws. 

One  of  the  clearest  demonstrations  of  the  dependence 
of  perception  upon  the  addition  of  memories  and  the 
recall  of  earlier  developed  ideas  is  found  in  the  fact  and 
nature  of  illusions.  In  all  forms  of  perception,  one  finds 
that  what  is  seen  or  heard  frequently  proves,  on  closer 
examination,  not  to  have  had  real  existence  in  the  out- 
side world,  or  to  have  existed  in  some  other  form  than 
that  in  which  it  was  perceived.  The  illusion  is  due  to 
one  of  two  causes.  The  sensations  suggest  the  wrong 
memories  or  ideas,  either  because  of  close  associations, 
or  because  the  wrong  context  or  setting  is  dominant  at 
the  moment.  The  influence  of  close  association  is  most 
clearly  shown  in  optical  illusions  of  space.  One  inter- 
pretation of  a  number  of  illusions  is  that  they  are  due 


PERCEPTION 


181 


FIG.  23. —  (From 
Titchener,  'Ex- 


to  a  suggestion  of  perspective  where  it  does  not  belong. 
One  of  the  most  general  applications  of  this  law  is  the 
tendency  to  overestimate  small  angles  and  to  under- 
estimate obtuse  angles.  Square  surfaces  are  nearly 
always  seen  in  perspective,  which  makes  right  angles 
appear  to  be  either  acute  or  obtuse.  The  most  frequent 
association  with  these  angles  is  a  right  angle,  —  an  over- 
estimation  of  the  small  and  an  underestimation  of  the 
large  angle.  This  association  that  has  become  fixed 
through  the  great  preponderance  of  rectan- 
gular objects  leads  to  error  in  many  differ- 
ent cases.  A  circle  with  a  square  inscribed 
seems  broken  at  the  corners  of  the  square, 
as  may  be  seen  in  Figure  23.  Where  an 
oblique  line  cuts  a  plane  figure  or  two  plane 
figures,  the  sections  of  the  line  seem  not  to 
be  continuous.  (See  Fig.  24.)  Both  illu-  pt.  i,  p.  160.) 
sions  can  be  referred  to  the  overestimation.  of  small  an- 
gles. A  more  complicated  figure,  that  may  be  explained 

as  due  to  the  over- 
estimation  of 
small  angles  or 
more  directly  as  a 
misapplication  of 
a  perspective  in- 
terpretation, is  the 
Hering  figure  (Fig. 
25).  In  this  fig- 
ure, the  oblique 
lines  are  taken  to 
represent  parallel 


\ 


\ 


FIG.  24.  —  Poggendorff  illusion.     (From  Titchener, 
op.  cit.,  p.  165.) 


182 


ESSENTIALS    OF   PSYCHOLOGY 


lines  converging  toward  a  vanishing  point ;  and  as  straight 
lines  drawn  on    such  surfaces  would    represent  curved 


s^         /        X////l\\\\          \        ^ 

FIG.  25.  —  Hering  figure.     (From  Titchener,  op.  cit.,  p.  161.) 


lines,  the  parallel  lines  are  assumed  to  diverge  in 
the  middle.  Both  can  be  explained  also  as  the  result 
of  overestimation  of  small  angles.  In  all  of  these  cases, 
the  figure  has  been  closely  associated  with  the  wrong 
interpretation,  and  the  interpretation  replaces  the  actual 


FIG.  26. —  Miiller-Lyer  illusion.     (From  Titchener,  op.  cit.,  p.  159.) 

figure.  Other  illusions  are  apparently  due  to  a  com- 
paiison  of  parts  of  the  figure  that  are  not  directly  in- 
volved. The  best  known  of  these  is  the  so-called  arrow- 
head or  Muller-Lyer  figure  (Fig.  26).  The  distance 
bounded  by  turned-out  arrow-heads  seems  much  larger 
than  that  bounded  by  those  that  turn  in.  It  is  prob- 
able that  one  really  judges  the  enclosed  area,  rather 


PERCEPTION  183 

than  the  distance  from  angle  to  angle.  The  perspective 
explanation  has  been  applied  to  this  figure  also,  on  the 
assumption  that  one  figure 
represents  a  book  opened 
away  from  the  observer, 
the  other  a  book  opened 
toward  the  observer.  This 
makes  one  line  seem  more 
distant  and  thus  larger  than 
the  other.  Another  illu- 
sion due  to  the  surround- 
ings is  the  underestimation  FIG.  27.  —  (From  Titchener,  op.  tit., 

Of  the    Upper     of     the    tWO  P- 166,  after  Wundt.) 

identical  figures  (Fig.  27).  The  upper  one  seems  small 
because  one  expects  both  to  be  bounded  by  the  same 
radii ;  the  failure  to  extend  to  that  line  makes  it  seem 
shorter  than  the  lower  that  does  reach  the  radii.  A  very 
large  number  of  optical  illusions  are  due  to  the  effects 
of  associations  that  are  misapplied  similarly,  and  a 
large  number  may  be  brought  under  these  two  principles 
of  misinterpretation  of  perspective,  and  of  arousal  of 
associates  by  the  surroundings,  rather  than  by  the  es- 
sentials. 

Illusions  that  illustrate  the  same  principle,  the  arousal 
of  wrong  associates,  may  be  found  in  any  field.  It  has 
been  shown  that  one  frequently  ascribes  motion  to  the 
wrong  object.  When  standing  on  a  bridge  over  a 
rapidly  flowing  stream,  one  can  easily  believe  that  the 
bridge  is  moving  upstream  and  the  water  is  stationary. 
This  is  due  to  the  fact  that  the  smaller  object  is  ordinarily 
in  motion,  the  ground  or  the  whole  field  of  vision  very 


184  ESSENTIALS   OF   PSYCHOLOGY 

seldom.  The  interpretation  more  frequently  associated 
with  the  sensations  asserts  itself  against  the  less  fre- 
quent. The  overlooking  of  misprints  in  reading  has  the 
same  explanation  as  has  the  shadow  lines  in  the  letters 
in  Figure  20,  page  158.  Many  misinterpretations  of  com- 
mon objects  can  be  referred  to  the  same  law.  Instances 
can  be  readily  supplied  by  the  reader.  Illusions  due  to 
the  dominance  of  the  wrong  context  or  to  the  wrong 
attitude  are  also  numerous.  If  one  is  expecting  any 
object,  anything  at  all  like  it  may  be  mistaken  for  it. 
If  one  is  listening  for  the  footsteps  of  one  person,  any 
passer-by  may  be  mistaken  for  him.  When  hunting  for 
cows  in  the  dark,  any  bush  or  dark  spot  takes  on  the 
form  of  the  cow.  Any  preconception  or  situation  that 
favours  one  interpretation  is  likely  to  favour  associates 
that  constitute  a  misinterpretation  or  illusion.  In 
general,  illusions  are  due  to  wrong  suggestions  by  sensa- 
tions, either  because  of  the  greater  strength  of  the  inap- 
propriate association,  or  because  the  situation  is  regarded 
in  the  wrong  attitude  of  mind.  Illusions  follow  the 
same  laws  as  perceptions ;  the  only  difference  is  that  in 
the  illusion  the  interpretation  is  proved  false  by  later 
observation  under  more  satisfactory  conditions. 

Hallucination.  —  Hallucinations  are  closely  related  to 
illusions.  Hallucinations  have  a  slighter  basis  in  sen- 
sation than  illusion,  and  derive  more  from  association. 
An  illusion  is  always  a  misinterpretation  of  an  object, 
while  in  hallucination  there  is  no  apparent  basis  for  the 
perception  in  sensation.  It  is  probable  that  the  absence 
of  sensation  is  in  most  cases  only  apparent,  and  that  the 
sensational  basis  may  be  found  in  some  slight  stimula- 


PERCEPTION  185 

tion,  as  in  the  after-image  for  the  visual  hallucination, 
and  in  the  circulation  or  some  abnormal  condition  of 
the  middle  ear  for  auditory  hallucination.  Even  in  the 
insane,  who  are  most  subject  to  hallucination,  there  is 
considerable  evidence  that  the  presence  of  the  false  ex- 
perience is  determined  by  some  obscure  stimulation  of  a 
sense-organ  that  is  misinterpreted  and  referred  to  the 
outer  world.  Thus  a  patient  may  insist  that  he  is  con- 
stantly hearing  voices  when  no  one  else  hears  them,  and 
with  no  apparent  cause.  On  examination  it  is  found 
that  he  suffers  from  a  disease  of  the  ear  that  produces  a 
constant  ringing  in  the  ear,  and  this  has  been  misinter- 
preted to  give  rise  to  the  hallucination.  The  only  dif- 
ference between  this  and  an  illusion  is  that  the  illusion 
on  examination  would  prove  to  arise  from  a  misinter- 
preted rustling  of  leaves  or  similar  objective  phenomenon. 
Perception  in  all  of  its  phases,  then,  is  due  to  the  inter- 
pretation of  a  present  sensation  by  organised  earlier 
experiences.  The  character  of  the  perception  depends 
upon  the  sensory  stimulus,  the  developed  ideas  the  in- 
dividual has  at  his  command,  and  the  connection  between 
these  and  the  sensations.  In  all  cases  of  perception,  the 
result  is  accepted  as  a  thing  in  the  outside  world,  and 
this,  the  final  outcome  of  the  process,  is  the  only  part 
that  is  noticed ;  all  else  is  overlooked. 

EXERCISES 

1.  Move  the  finger  in  a  circle  before  the  face  with  closed  eyes. 
Do  you  appreciate  the  motion  in  the  arm  or  do  you  see  it  with  the 
mind's  eye  ?     How  is  the  picture  suggested  ? 

2.  Have  some  one  touch  you  on  the  wrist  while  the  eyes  are  closed, 


1 86  ESSENTIALS   OF   PSYCHOLOGY 

Try  to  touch  the  point.  Measure  the  error  and  repeat  twenty 
times.  Average.  Is  the  first  touch  more  or  less  accurate  than  the 
point  finally  decided  upon  ?  How  do  you  know  what  point  was 
touched  ? 

3.  Compare  two  lines  20  and  21  mm.  in  length.     Can  you  tell 
which  is  the  longer  ?    Do  the  eyes  move  in  the  comparison  ?     Can 
you  compare  with  the  eyes  stationary  ? 

4.  Draw  a  horizontal  line  20  mm.  long.     Without  measuring  try 
to  place  a  point  20  mm.  above  one  end  of  the  line.     Measure  the 
distance.     Repeat  twenty  times.     Average.     Explain  result.     Re- 
peat, putting  the  point  above  the  centre  of  the  line.    How  do  the 
results  compare?    Explain  the  difference. 

5.  Hold  a  bottle  with  a  label  on  it  about  30  cm.  before  the  nose. 
Close  first  one  eye,  then  the  other.     Note  the  difference  in  the 
images.     Place  the  bottle  six  metres  away.     Compare  the  image 
as  before.    Where  is  the  difference  between  the  images  greater? 
Can  you  see  the  difference  in  the  images  with  both  eyes  open? 
What  is  the  bearing  upon  the  perception  of  distance  ? 

6.  Hold  the  index  fingers  25  cm.  apart  before  the  eyes.    Look 
at  the  more  distant  finger  and  note  the  double  images  of  the  nearer. 
Close  one  eye.    Which  image  vanishes?     Look  at  the  nearer 
finger.     Which  image  of  the  more  remote  finger  vanishes  when  one 
eye  is  closed  ?    Look  at  a  point  6  m.  distant.     Can  you  notice  the 
double  images  of  nearer  and  more  remote  objects  ?    How  do  the 
double  images  vary  in  distance  from  each  other  as  they  depart  from 
the  point  of  fixation  ? 

7.  Have  some  one  tap  a  two-second  interval  and  attempt  to  re- 
produce the  interval.     How  accurate  are  you  ?     Can  you  notice 
strain  or  other  sensations  during  the  interval  ?    Do  they  seem  to 
affect  the  comparison  ? 

8.  Watch  the  eyes  of  some  one  when  reading  at  the  ordinary  rate. 
How  many  pauses  do  the  eyes  make  to  the  line  on  the  average  ? 
Compare  reading  a  newspaper  with  a  page  of  an  unfamiliar  chapter 
of  this  text.    Try  when  reading  to  detect  misprints.     In  which  in- 
stance are  the  words  relatively  prominent  as  compared  with  ideas  ? 

9.  Draw  a  vertical  line  with  an  oblique  line  across  it.     Can  you 


PERCEPTION  187 

see  the  figure  as  a  cross  with  the  arm  perpendicular  to  the  upright, 
but  in  some  other  plane  than  th'e  plane  of  the  paper  ?  What  bear- 
ing has  this  upon  the  interpretation  of  the  illusion  of  overestimation 
of  small  angles  ? 

REFERENCES 

ANGELL  :  Psychology,  ch.  vi. 

TITCHENER  :  Text-book  of  Psychology,  pp.  303-374. 

JUDD  :  Psychology,  ch.  vi. 

PILLSBURY  :  Attention,  ch.  viii. 

JASTROW  :  Fact  and  Fable  in  Psychology,  pp.  275-295. 

SEASHORE  :  Elementary  Experiments  in  Psychology,  ch.  iv-vi,  xiv. 


CHAPTER  VIII 

MEMORY  AND  IMAGINATION 

MEMORY,  imagination,  and  reasoning  are  related  to 
simple  imagery  very  much  as  perception  is  related  to 
sensation.  Each  may  be  analysed  into  simple  sensational 
or  imaginal  qualities,  and  each  follows  the  laws  of  asso- 
ciation. Each  deals  with  things,  is  concrete,  as  op- 
posed to  sensations  and  images  that  are  pure  abstrac- 
tions. Each  is  an  attempt  to  understand  the  world  and 
prepares  for  action  in  the  world.  The  thought  processes 
differ  from  perception  in  the  time  and  place  to  which 
the  event  is  referred.  In  perception  it  is  actually  pre- 
sented to  the  senses  at  the  moment;  in  the  three  pure 
thought  processes,  it  is  regarded  as  past  or  future  or  as 
having  real  existence  in  some  distant  place.  The  only 
other  difference  is  that  perception  contains  some  sensa- 
tional elements,  while  the  others  are  altogether  of  central 
origin.  Memory,  imagination,  and  reasoning  differ  from 
each  other,  also,  in  the  temporal  reference  and  the  atti- 
tude that  is  taken  toward  the  object  or  event  which 
they  represent.  Memories  are  all  ascribed  to  the  past, 
while  reasoned  and  imagined  events  may  be  past,  present, 
or  future.  Memories  and  the  results  of  reasoning,  again, 
are  accepted  as  true,  imaginings  are  without  implication 
of  truth.  Otherwise  they  are  not  to  be  distinguished. 
Each  may  be  made  up  of  the  same  elements.  One  may 

188 


MEMORY   AND   IMAGINATION  189 

imagine  an  event,  later  reason  that  it  is  sure  to  happen, 
have  this  conclusion  confirmed  by  the  actual,  and  later 
remember  it,  —  all  in  the  same  imagery.  They  are  all 
three  suggested  and  determined  in  their  course  by  the 
laws  of  association.  Not  the  materials  or  the  laws  of 
origin  distinguish  these  states  from  each  other,  but  the 
attitude  that  is  taken  toward  them  and  the  points  in 
time  and  space  to  which  they  are  referred. 

The  Phases  of  the  Memory  Process.  —  We  may  begin 
our  discussion  of  thought  processes  with  memory. 
Memory  is  a  reinstatement  of  an  old  experience,  or  a 
present  consciousness  of  an  old  experience,  with  the 
knowledge  that  it  is  old.  Four  fairly  distinct  processes 
are  involved  in  memory,  —  learning,  retention,  recall, 
and  recognition.  These  cannot  always  be  distinguished 
in  practice,  but  they  require  separate  treatment  if  mem- 
ory is  to  be  understood.  Any  one  of  them  would  be 
valueless  without  the  others.  Learning  without  reten- 
tion is  almost  a  contradiction  in  terms.  Retention 
without  recall  is  equally  futile.  Retention,  hi  fact,  can 
be  demonstrated  only  through  recall.  The  knowledge 
that  is  stored  in  your  brain  at  this  moment  gives  no 
sign  of  its  presence.  You  can  be  aware  of  what  you 
know  only  by  recalling  it.  Finally,  if  events  when  re- 
called were  not  recognised,  recall  would  be  valueless.  If 
when  an  idea  came  to  mind  you  could  not  say  whether 
it  was  derived  from  a  dream  or  a  real  experience,  it 
would  be  merely  confusing.  Statements  that  you  re- 
member you  have  read  but  cannot  tell  where  or  when 
can  be  little  relied  upon.  Only  ideas  that  can  be  referred 
to  some  definite  time  and  place  in  your  past  can  be  used 


igO          ESSENTIALS  OF  PSYCHOLOGY 

in  any  way;    others  are  not  worth  recalling.     Each  of 
these  processes  must  be  taken  up  in  order. 

In  all  discussion  of  memory,  it  is  essential  to  recognise 
two  distinct  forms,  rote  memory  and  logical  memory. 
In  rote  learning  connections  are  formed  between  the  suc- 
cessive ideas  or  elements  that  are  to  be  learned,  and  re- 
call is  always  from  one  to  another  of  these  elements. 
In  logical  learning,  on  the  contrary,  the  material  to  be 
learned  is  connected  with  the  organised  knowledge  of  the 
individual;  it  is  understood,  and  learned  because  it  is 
understood.  Most  learning  in  everyday  life  is  of  the 
logical  sort.  We  acquire  ideas,  not  words,  and  the 
ideas  are  assimilated  at  once  to  the 'ordered  experiences. 
This  is  much  quicker  and  more  effective  than  rote  learn- 
ing. We  must  consider  both  forms  in  each  stage  of  the 
memory  process.  Practically  all  of  the  experimental 
work  in  memory,  of  which  there  has  been  a  great  volume 
in  recent  years,  has  dealt  with  rote  learning.  It  is  much 
easier  to  measure  than  logical  learning.  Nonsense  syl- 
lables were  chosen  as  the  material  to  be  learned  in  these 
experiments,  since  these  were  completely  new  to  all  of 
the  learners  and  all  the  syllables  were  equally  new.  Non- 
sense syllables  were  made  by  placing  a  vowel  between 
pairs  of  consonants  and  eliminating  all  of  the  combina- 
tions that  made  words.  From  these  syllables  series  of 
from  eight  to  sixteen  were  chosen  and  shown  to  the 
learner  by  means  of  an  instrument  at  regular  intervals. 
The  number  of  times  they  were  shown  was  recorded. 
Tests  as  to  the  amount  retained  were  made  after  dif- 
ferent intervals  to  measure  the  amount  of  retention,  and 
thus  determine  the  relative  value  of  the  methods  of  learn- 


MEMORY   AND   IMAGINATION  1 9! 

ing.  A  large  number  of  results  have  been  obtained  from 
these  experiments,  and  we  can  profitably  begin  our  dis- 
cussion of  the  memory  process  by  a  summary  of  the 
laws  that  they  have  established,  so  far  as  they  may  be 
applied  in  practice. 

The  Laws  of  Learning.  —  Learning,  the  first  step  ia 
memory,  is  only  a  process  of  forming  associations.  Rote 
learning  is  primarily  a  process  of  forming  associations 
between  series  of  words  or  events,  —  in  the  experiments 
we  are  considering,  connections  were  formed  between 
nonsense  syllables.  The  experiments  were  devised  to 
determine  the  best  methods  of  establishing  connections 
between  the  syllables.  The  results  may  be  stated  in  a 
series  of  brief  laws. 

1.  Learning  is  directly  dependent  upon  the  number 
of  repetitions.     If  two  repetitions  induce  a  given  liability 
to  recall,  four  will  give  double  the  liability,  and  others 
in  proportion.     It  may  be  emphasised  that  this  rule 
holds  beyond  the  point  where  the  material  is  apparently 
completely    learned,  —  that    is,    after    it    may  be    said 
through  once  without  mistake.     After  the  learning  is 
completed,  the  added  repetitions  increase  retention  al- 
though at  the  moment  no  effect  is  apparent. 

2.  Capacity  for  learning  increases  with  age  up  to  the 
period  of  maturity,  and  then  remains  constant  until  the 
beginning  of  old  age.     The  popular  belief  that  children 
learn  better  than   adults  has  no  basis  in  fact.     It  is 
due    apparently    to    the    child's    closer    observation    of 
routine  events,  and  to  the  frequency  with  which  events 
of  childhood  are  recalled  on  account  of  their  original 
interest.     When  tested  in  any  accurate  way,  the  child 


1 92  ESSENTIALS   OF   PSYCHOLOGY 

is  found  to  learn  less  easily  and  to  retain  less  than  the 
adult. 

3.  Learning  is  easier  if  the  repetitions  be  distributed 
over    several   days,    rather    than    accumulated    on    a 
single  day.     It  is  found  that  the  most  effective  learning 
that  can  be  obtained  with  twenty-four  repetitions  will 
be  obtained  if   two   repetitions  are  made  on  each  of 
twelve  days.     That  is  more  effective  than  four  repetitions 
on  six  days,  or  six  on  four  days.     Any  distribution  will 
be  better  than  to  have  twenty-four  on  one  day.     This 
is  due  largely  to  the  fact  that  the  change  induced  in  the 
nerve-cells  by  learning  increases  during  the  period  be- 
tween repetitions.     The  new  repetitions  add  more  to  the 
old  when  its  effects  have  had  time  to  '  set,'  —  to  become 
more  completely  incorporated  in  the  nervous  tissue.     It 
is  a  common  observation  that  a  lesson  is  better  learned 
if  one  will  prepare  it  on  one  day  and  review  it  the  next 
morning,  than  if  one  prepares  it  more  thoroughly  at  the 
first  sitting,  —  an  instance  of  distributed  repetitions. 

4.  In  learning  a   selection,   it  is   advisable   to   read 
through  the  whole  from  beginning  to  end,  and  to  repeat 
the  reading  until  all  is  learned,  rather  than  to  learn  bit 
by  bit.     If  one  attempts  to  learn  a  poem  line  by  line  or 
stanza  by  stanza,  one  makes  a  number  of  unnecessary 
and  misleading  associations  between  the  ends  and  the 
beginnings  of  lines  that  both  waste  time  and  interfere 
with  the  correct  associations.     Then,  too,  learning  by 
parts  leads  to  the  repetition  of  the  first  portions  more 
frequently  than  is  necessary,  since  they  are  repeated 
with  each  of  the  later  parts.     The  only  objection  to 
learning  by  wholes  is  that  one  is  likely  to  lose  interest 


MEMORY    AND    IMAGINATION  193 

in  the  work  when  no  progress  can  be  noticed,  and  to 
read  more  slowly  than  usual.  This  may  be  obviated 
by  making  pauses  at  the  natural  points  of  division  with- 
out going  back  to  the  beginning.  It  is  also  advisable, 
after  the  selection  is  partly  learned,  to  repeat  the  harder 
parts  more  frequently  than  the  easier.  These  methods 
combine  the  marked  advantage  of  learning  as  a  whole 
with  the  greater  interest  that  comes  from  observing 
progress  in  the  task.  When  this  rule  was  observed, 
some  investigators  demonstrated  a  saving  of  as  much 
as  twenty  per  cent  in  the  repetitions  required  for 
learning. 

5.  Learning  is  quickest  if  the  rate  of  repetition  is  as 
fast  as  is  convenient  for  the  man  who  is  learning.     Slower 
repetitions  waste  time  and  permit  distraction ;    faster 
distract  attention  from  the  learning  to  the  articulation. 
As  many  as  two  hundred  syllables  a  minute  have  been 
found  most  advantageous  for  some  individuals.     When 
a  student  has  been  compelled  to  postpone  preparation 
of  a  lesson  to  a  short  period  before  the  recitation,  unex- 
pected results  are  shown  for  the  time  spent.     Rapid 
reading  is  of  less  value  for  material  that  requires  thought 
than  for  rote  learning.     Slower  reading  permits  the  for- 
mation of  more  associates;    rapid  reading  gives  strong 
associates  with  the  preceding  and  succeeding  elements, 
but  gives  no  time  for  others  that  might  be  important. 

6.  Rhythm  is  a  great  aid  to  learning.     It  is  difficult 
to  avoid  rhythm,  and  best  results  may  be  obtained  from 
a  rhythm  adapted  to  the  material  and  to  the  individual 
peculiarities  of  the  learner.     The  strongest  connections 
are  made  between  the  elements  of  the  rhythmic  unit. 

o 


IQ4  ESSENTIALS   OF   PSYCHOLOGY 

When  the  rhythm  is  changed  or  elements  are  given  a 
place  in  a  new  unit,  relearning  or  retention  is  much 
interfered  with.  The  importance  of  rhythm  is  shown 
by  the  ease  with  which  blank  verse  may  be  learned. 

All  learning,  then,  is  a  process  of  forming  associations ; 
and  all  rote  learning,  with  much  of  other  learning,  de- 
pends for  its  adequacy  upon  the  use  of  suitable  methods 
of  repetition.  To  translate  into  nervous  terms,  learning 
is  a  process  of  producing  changes  in  the  synapses.  This 
change  depends  directly  upon  the  number  of  repetitions, 
upon  the  age  of  the  individual,  upon  the  time  that 
elapses  before  one  repetition  is  succeeded  by  another, 
and  by  the  rhythm  and  rate  of  repetitions.  Proper 
control  of  these  factors  and  of  attention  gives  the  means 
of  easiest  and  most  complete  learning. 

Laws  of  Retention  or  of  Forgetting.  —  If  learning  is 
the  result  of  producing  changes  in  the  synapses,  reten- 
tion depends  upon  the  persistence  of  the  impression; 
forgetting,  upon  its  disappearance.  That  the  impres- 
sions fade  and  gradually  disappear  with  the  passage  of 
time  is  obvious,  but  the  rate  of  disappearance  and  the 
conditions  that  favor  or  retard  the  disappearance  can 
be  determined  only  by  experiments.  The  same  pro- 
cedure that  gave  us  the  laws  of  learning  has  also  de- 
veloped a  series  of  laws  of  forgetting.  We  may  sum- 
marise these  as  before. 

i.  Forgetting  goes  on  very  rapidly  at  first,  then  more 
slowly,  until  finally  there  is  no  appreciable  change  even 
over  long  periods  of  time.  Ebbinghaus  found  that  with 
series  of  nonsense  syllables,  half  of  the  learning  was  lost 
in  the  first  hour ;  two-thirds  the  first  day ;  while  at  the 


MEMORY  AND   IMAGINATION  1 95 

end  of  the  month,  less  than  four-fifths  was  forgotten. 
Meumann  obtained  the  same  general  law,  but  with  a 
slower  rate  of  forgetting  for  the  shorter  periods.  In 
ordinary  learning,  details  disappear  very  quickly,  while 
the  more  general  principles  are  remembered  for  a  long 
time.  Both  in  sense  and  nonsense  material,  traces  of 
learning  persist  long  after  all  possibility  of  recall  in  the 
ordinary  way.  In  the  experiments,  the  amount  of  for- 
getting is  measured  by  comparing  the  number  of  repeti- 
tions needed  for  relearning  after  the  lapse  of  some  definite 
time  with  the  number  of  repetitions  used  in  the  original 
learning.  Thus,  if  sixteen  repetitions  are  required  for 
learning  a  series  of  twelve  syllables,  eight  repetitions 
might  be  necessary  to  relearn  at  the  end  of  the  hour. 
After  three  days,  no  single  one  of  the  syllables  might  be 
recalled  off-hand,  but  it  would  be  found  that  all  might 
be  relearned  in  ten  repetitions.  In  much  practical  learn- 
ing, the  same  rule  holds.  One  may  have  forgotten  all 
about  a  principle  in  arithmetic,  but  will  find  that  it  can 
be  relearned  in  a  fraction  of  the  time  originally  given  to 
it.  Not  a  little  of  the  benefit  of  learning  is  found  in 
this  increased  ease  of  relearning,  even  where  nothing 
can  be  recalled  spontaneously.  Forgetting  is  much 
slower  for  sense  material  than  for  nonsense.  Ebbing- 
haus  found  that  half  was  retained  at  the  end  of  twenty- 
four  hours,  as  compared  with  one-third  for  nonsense  syl- 
lables. He  was  able  to  demonstrate  a  saving  of  seven 
per  cent  in  relearning  poetry  after  the  lapse  of  twenty- 
one  years. 

2.  After  learning,  the  degree  of  retention  is  affected 
by  mental  activity  of   any   sort.     If,  after  learning  a 


196          ESSENTIALS  OF  PSYCHOLOGY 

series  of  nonsense  syllables,  one  turns  at  once  to  learn- 
ing something  else  or  to  any  form  of  mental  work,  it  is 
found  that  retention  is  less  complete  than  if  one  rests  a 
few  minutes.  The  new  work  seems  to  interfere  with 
some  continuing  activity  of  the  nervous  system  that  is 
essential  to  the  best  retention.  This  '  setting  '  of  the 
associations  after  learning  is  probably  what  makes  dis- 
tributed repetitions  more  effective  than  accumulated 
ones.  It  is  also  connected  with  the  memory  after- 
image, that  has  been  mentioned  in  previous  chapters 
(vide,  p.  134).  The  nerve-cells  continue  to  act  for  some 
little  time  after  the  conscious  processes  have  ceased, 
and  the  associations  continue  to  increase  in  strength 
during  this  period.  New  work  interferes  with  this 
activity,  and  prevents  the  associations  from  reaching 
their  full  strength.  This  so-called  retroactive  inhibition 
is  analogous  to  the  retrograde  amnesia  of  the  psychia- 
trist. This  technical  term  means  that  a  mental  or  phys- 
ical shock  will  destroy  memories  of  events  that  have 
immediately  preceded,  and  that  may  be  assumed  to  be 
represented  by  associations  that  have  not  completely 
'  set.'  A  fall  or  blow,  that  affects  the  head,  often  obliter- 
ates the  memories  of  events  that  have  occurred  for  a 
half  hour  or  more  before.  An  emotional  shock  may 
have  the  same  effect.  In  our  present  connection,  hard 
mental  work  exerts  the  same  influence  in  smaller  degree. 
A  lesson  will  be  better  remembered,  if  one  will  wait 
three  to  six  minutes  after  finishing  it  before  turning  to 
another  task. 

.  3.  Generative  Inhibition.  —  Ideas  learned  in  one  con- 
nection seem  to  be  more  difficult  to  learn  in  another 


MEMORY  AND    IMAGINATION  197 

connection.  If  idea  '  A  '  has  been  learned  in  connection 
with  an  idea  '  B,'  it  will  be  more  difficult  to  learn  it  in 
connection  with  another  idea  '  C,'  than  if  the  other  as- 
sociation had  not  been  formed.  Learning  anything  in- 
correctly makes  correct  learning  more  difficult.  The 
wrong  associations  check  the  formation  of  the  correct 
associations.  Generative  inhibition  is  effective  only 
when  the  first  set  of  associates  has  not  been  completely 
formed.  After  complete  learning,  the  one  set  of  asso- 
ciations may  make  easier  the  formation  of  others  of  the 
same  kind.  If,  for  example,  one  has  partly  learned  one 
style  of  typewriter  key-board,  it  is  much  more  difficult 
to  learn  another ;  but  if  the  first  has  been  thoroughly 
learned  before  one  begins  the  second,  the  second  will  be 
learned  more  quickly  than  the  first.  The  same  holds  in 
some  degree  of  learning  languages. 

4.  Effectual  Inhibition.  —  Associates  with  the  same 
idea,  not  only  interfere  with  each  other  in  the  formation, 
but  also  prevent  the  recall  of  the  ideas.  If  one  has 
learned  '  A  '  with  '  B,'  '  C,'  and  '  D,'  and  '  A  '  is  un 
consciousness,  the  recall  of  any  one  of  the.  associates 
may  be  prevented,  or  at  least  delayed.  All  associates 
tend  to  return,  and  each  helps  to  prevent  the  return  of 
the  others.  This  mutual  interference  of  associates  is 
probably  the  explanation  of  many  cases  of  mental  block- 
ing. Often  when  one  is  trying  to  recall  a  perfectly  fa- 
miliar fact,  it  refuses  to  return.  It  seems  to  be  on  the 
tip  of  the  tongue,  but  cannot  be  expressed.  Later,  when 
the  occasion  for  its  recall  has  passed,  it  will  return  with 
perfect  ease.  It  is  probable  that  the  cue  was  associ- 
ated with  several  ideas,  and  that  they  mutually  prevented 


198  ESSENTIALS   OF   PSYCHOLOGY 

the  return  of  anyone.  When  recall  occurs,  probably  all 
but  one  of  the  associates  have  ceased  to  be  active. 
Ordinarily  some  one  associate  will  be  much  stronger 
than  the  others,  or  will  be  favored  by  the  context  or 
'  mental  set,'  and  the  opposition  of  the  others  is  ineffec- 
tive. 

5.  Individuals  who  learn  easily  seem  to  forget  slowly 
while  those  who  learn  slowly  forget  rapidly.  This  law 
holds  if  one  considers  pure  rote  learning.  When  learn- 
ing sense  material  by  logical  connections,  the  man  who 
learns  slowly  may  have  an  advantage  if  he  gives  the 
added  time  to  understanding  the  matter.  In  this  case 
the  evidence  shows  that  slow  learning  is  compensated  for 
by  retentive  memory.  The  conditions  and  results  are 
somewhat  in  dispute. 

All  learning  and  retention,  then,  are  dependent  upon 
the  formation  and  persistence  of  associations.  Learn- 
ing and  retention  are  never  of  idea's  or  things  in  isola- 
tion, but  always  of  things  in  connection.  The  only 
laws  that  affect  learning  are  the  laws  for  the  easy  and 
quick  formation  of  associations,  and  for  preventing  inter- 
ference with  them  when  they  are  formed.  No  new  prin- 
ciples need  be  added  to  the  discussion  of  association  to 
understand  rote  learning  and  retention. 

The  Advantages  of  Forgetting.  —  One  is  inclined  to 
think  of  forgetting  as  altogether  a  disadvantage.  This 
is,  however,  not  the  case.  On  the  contrary,  if  every- 
thing were  remembered,  it  would  probably  be  a  great 
misfortune.  Many  of  the  trivial  events  of  everyday 
life  are  very  much  better  forgotten.  Forgetting  is  an 
expression  of  the  selective  activities  of  consciousness, 


MEMORY   AND    IMAGINATION  1 99 

and  is  almost  if  not  quite  as  important  as  attention  in 
protecting  the  individual  against  the  unessential  events. 
Attention  very  largely  determines  what  shall  be  selected, 
both  for  observation  and  retention,  although  it  may 
work  different  results  for  each,  since  many  things  that 
are  important  at  the  moment  are  not  worth  remember- 
ing. Forgetting  plays  its  part  in  permitting  these  to 
lapse  into  unconsciousness.  A  good  memory  involves  a 
certain  amount  of  forgetting,  provided  only  the  right 
things  are  forgotten.  The  possibility  of  forgetting  is  an 
advantage,  not  only  in  that  it  permits  the  trivial  events 
to  be  forgotten,  but  because  it  makes  it  possible  to  for- 
get things  that  were  learned  wrongly.  If  one  remem- 
bered everything,  the  bad  would  survive  with  the  good. 
As  it  is,  when  a  mistake  has  been  made  and  corrected, 
the  correction  may  be  remembered,  the  mistake  for- 
gotten. On  the  whole,  then,  the  fact  that  the  memory 
trace  in  the  nervous  system  tends  to  disappear  is  an 
advantage  rather  than  a  disadvantage.  In  some  cases 
where  no  distinction  is  made  between  the  important  and 
the  unimportant,  the  individual  is  rendered  ineffective. 
Slavery  to  routine  often  leads  to  waste  of  time  and 
effort  that  a  bad  memory  might  prevent.  Forgetting  is 
almost  as  important  as  remembering  in  the  adequate  use 
of  past  experiences. 

Recall.  —  The  laws  of  recall,  too,  are  primarily  the 
laws  of  association.  If  everything  that  is  learned  must 
be  learned  in  connection  with  something  else,  it  follows 
that  anything  that  is  recalled  must  be  recalled  because 
of  the  rearousal  of  an  associate.  This  can  be  brought 
about  only  through  the  presence  of  some  cue,  some  idea 


200  ESSENTIALS    OF    PSYCHOLOGY 

that  has  been  associated  with  the  fact  that  is  essential 
at  the  moment.  One  cannot  recall  an  idea  without  the 
associated  idea  or  sensation.  It  is  impossible  to  get 
back  the  fact  in  any  other  way  than  through  the  ap- 
propriate suggestion.  This  suggestion  may  be  furnished 
by  the  preceding  idea  or  it  may  come  through  sensa- 
tion. Fortunately  nearly  every  fact  has  been  asso- 
ciated with  the  occasions  that  make  its  return  desirable, 
and  in  consequence  one  never  suffers  from  or  even  notices 
the  lack  of  more  direct  means  of  recall.  The  desire  for 
recall  brings  its  satisfaction,  and  that  is  all  that  can  be 
asked.  The  laws  of  recall  come  into  prominence  only 
when  they  fail  to  be  effective.  Occasionally  one  is  cer- 
tain that  one  has  a  bit  of  knowledge  that  would  be 
desirable  at  the  moment,  but  which  cannot  be  recalled. 
Under  such  circumstances,  one  of  -two  factors  is  at 
fault.  Either  no  association  has  been  formed  between 
the  idea  in  mind  and  the  idea  desired,  or  the  mental 
attitude  is  wrong  for  developing  that  association.  These 
are  the  conditions  for  the  return  of  associations  discussed 
in  Chapter  V.  The  one  can  be  obviated  only  at  the 
time  the  associations  are  formed,  is  due  to  the  nature  of 
the  learning;  the  other  depends  upon  the  condition  of 
the  thinker  at  the  moment  of  recall. 

Certain  and  accurate  recall  depends  primarily  upon 
the  methods  of  learning ;  it  is  only  in  part  subject  to 
control  at  the  moment  of  recall.  The  only  rule  that  can 
be  given  for  the  improvement  of  recall  is  to  learn  a  new 
fact  in  connection  with  all  of  the  possible  situations 
where  it  might  be  used  to  advantage.  Most  learning  is 
in  one  connection  only  or  in  a  few  at  most.  The  value 


MEMORY   AND    IMAGINATION  2OI 

of  a  fact  increases  with  the  number  of  connections  that 
it  makes,  for  each  new  connection  makes  it  available  in 
a  new  place  and  at  a  new  time.  These  valuable  con- 
nections can  be  supplied  by  taking  time  to  think  of  the 
various  uses  that  a  new  fact  may  have,  or,  more  effec- 
tively, by  actually  applying  it.  A  formula  in  trigonom- 
etry will  be  impressed  much  more  surely  and  will  be 
recalled  in  many  more  appropriate  situations  if  a  num- 
ber of  problems  involving  it  are  solved  in  connection 
with  it.  Each  of  these  applications,  when  they  appear 
in  practice,  will  suggest  the  principle;  while  without 
them,  only  the  preceding  statements  in  the  text  will 
recall  it,  and  these  are  seldom  present  when  occasion 
arises  for  its  recall  in  practice.  In  general,  learning  any 
new  fact  in  all  the  connections  where  it  can  be  used  will 
insure  perfect  recall  so  far  at  least  as  it  may  be  insured 
at  the  moment  of  learning. 

The  other  element  in  recall  depends  upon  having  the 
correct  attitude  toward  the  situation  when  it  presents 
itself.  If  one  does  not  properly  appreciate  the  situation, 
the  associates  that  might  be  used  at  the  time  will  fail 
to  be  recalled.  One  is  looking  at  the  problem  in  the 
wrong  way,  and  a  number  of  solutions  that  harmonise 
with  the  attitude  will  present  themselves,  but  they  will 
not  be  solutions  of  this  problem.  Both  sorts  of  failure 
to  recall  may  be  observed  in  any  class  recitation.  When 
a  question  is  asked,  it  should  serve  as  a  cue  for  the  an- 
swer. In  many  if  not  most  cases,  the  failure  to  answer 
does  not  depend  upon  lack  of  knowledge,  as  is  proved 
by  the  fact  that  the  answer  will  be  recognised  when  it 
is  given.  What  is  wrong  is  the  failure  to  connect  the 


202  ESSENTIALS    OF    PSYCHOLOGY 

answer  with  the  question  at  the  time  it  was  learned.  It 
was  learned  in  some  other  connection,  and  is  useless  as 
an  answer  to  this  question.  In  the  second  place,  the 
question  may  be  understood  in  the  wrong  way.  The 
question  may  have  been  connected  with  the  answer  when 
understood  in  one  way,  but,  at  the  moment,  the  student 
is  thinking  of  the  question  in  one  way,  the  instructor  in 
another.  The  result  is  that  the  answer  suggested  does 
not  meet  the  problem  that  the  instructor  has  put.  Ade- 
quate recall  depends,  first,  upon  having  the  material; 
then  upon  having  the  knowledge  associated  with  an  idea 
or  object  that  is  present  when  it  is  needed ;  and  finally, 
upon  being  in  a  suitable  attitude  toward  the  situation. 
The  first  two,  learning  and  learning  in  the  right  connec- 
tions, can  of  course  be  insured  only  before  the  time  the 
knowledge  is  to  be  used.  The  attitude  is  the  only 
factor  determined  at  the  time  of  recall,  and  that  is  not 
easily  controlled.  It  depends  upon  the  agility  of  the 
wits  of  the  thinker,  and  upon  the  things  he  has  been  see- 
ing or  thinking  just  before.  The  most  that  can  be  done 
in  the  control  of  the  attitude  is  to  teach  the  individual  to 
look  at  a  situation  in  many  ways,  and  to  trust  his  memory. 
Taking  the  right  attitude  is  in  large  part  due  to  native 
endowment,  but  training  or  practice  has  some  effect. 

Logical  as  Opposed  to  Rote  Learning.  —  So  far,  we 
have  been  discussing  memory  as  if  all  associations  were 
formed  at  once,  and  as  if  all  learning  dealt  with  entirely 
new  knowledge.  As  a  matter  of  fact,  however,  most 
learning  consists  in  bringing  the  new  material  into  con- 
nection with  old  knowledge,  or  in  seeing  old  knowledge 
in  new  lights.  When  one  is  reading  even  in  a  new  sub- 


MEMORY   AND   IMAGINATION  203 

ject,  one  is  constantly  referring  what  is  read  to  earlier 
knowledge,  rather  than  taking  the  new  as  new.  We  can 
bring  ourselves  to  read  very  little  of  what  we  do  not 
understand,  yet  to  understand  means  nothing  more  than 
to  refer  the  new  to  old  knowledge  or  old  principles. 
What  is  understood  is  learned  very  quickly,  —  even  by 
a  single  repetition.  A  large  part  of  the  work  necessary 
for  learning  was  done  when  the  principles  themselves 
were  learned  and  does  not  need  to  be  done  again.  All 
that  is  necessary  is  to  connect  the  new  with  the  old,  and 
the  new  then  takes  on  the  permanence  of  the  old. 

The  advantages  of  logical  learning  are  twofold.  In 
the  first  place,  as  was  indicated  above,  when  one  under- 
stands, the  material  is  partly  known  already,  and  so 
needs  fewer  repetitions  to  be  remembered.  In  the  second 
place,  there  are  many  more  facts  than  principles,  and 
the  principles  are  used  so  frequently  in  different  connec- 
tions that  they  become  part  of  the  permanent  endow- 
ment. Specific  instances  may  appear  and  be  forgotten, 
but  the  general  principles  illustrated  are  used  over  and 
over  and  thus  are  given  no  chance  to  be  forgotten. 
When  the  new  fact  or  experience  is  understood  by  being 
referred  to  this  system  of  principles,  it,  too,  comes  to 
partake  somewhat  of  their  permanent  character.  One 
may  notice  in  the  simplest  affairs  the  difference  between 
the  bare  unaided  memory  and  this  memory  of  general 
principles.  In  playing  golf,  for  example,  one  may  either 
remember  in  a  vague  general  way  where  the  ball  has  been 
driven,  or  may  fix  the  place  by  specific  reference  to  a 
prominent  object.  If  one  just  notices,  one  may  at  once 
walk  to  the  ball  with  no  other  thought  than  that  one  is 


204  ESSENTIALS    OF   PSYCHOLOGY 

going  in  the  right  direction.  Under  ordinary  circum- 
stances this  suffices,  but  if  one  is  turned  aside  to  hunt  the 
ball  of  the  opponent,  or  the  stroke  is  bad  and  arouses  an 
emotion,  the  pure,  unmediated  memory  is  destroyed; 
one  retains  but  the  vaguest  idea  of  the  direction  of  the 
ball.  If,  however,  one  refers  the  position  to  some  fixed 
point,  refers  it  to  a  system,  the  position  will  be  remem- 
bered in  spite  of  distraction,  and  for  a  considerably 
longer  time. 

Nearly  all  of  the  experiments  that  have  been  made, 
the  results  of  which  have  been  formulated  in  the  earlier 
sections,  have  been  made  with  nonsense  syllables,  and, 
in  consequence,  hold  only  for  the  raw  memory  rather 
than  for  the  logical  memory  that  is  used  in  most  practical 
work.  Logical  memory  undoubtedly  follows  the  same 
general  laws,  and  the  principles  may  be  applied  to  it  with 
allowances  for  slight  differences  in  amount.  How  great 
the  differences  may  be  has  not  been  accurately  deter- 
mined. Ebbinghaus  found  that  learning  poetry  verbatim 
takes  less  than  half  the  time  required  for  nonsense  sylla- 
bles, but  memory  for  the  sense  of  ordinary  reading  matter 
must  have  a  much  larger  advantage.  Long  passages  that 
would  require  days  for  their  verbatim  learning  can  be  ap- 
preciated and  the  ideas  retained  with  one  reading.  The 
rate  of  forgetting  is  also  much  slower.  A  fact  thoroughly 
understood  may  be  remembered  for  a  large  part  of  a  life- 
time with  little  or  no  deterioration.  Accurate  experi- 
ments on  the  course  of  recognition  indicate  that  objects, 
that  may  be  referred  to  standards  or  general  principles, 
are  recognised  practically  as  well  after  a  longer  as  after  a 
shorter  time,  while  sensations,  to  which  no  names  can  be 


MEMORY  AND   IMAGINATION  2O$ 

given  or  which  can  be  referred  to  no  general  principle, 
lose  their  value  for  recognition  at  about  the  same  rate 
that  nonsense  syllables  are  forgotten.  While  there  is  no 
experimental  evidence  that  bears  directly  upon  the  point, 
what  evidence  there  is  together  with  the  results  of  obser- 
vation indicates  that  logical  learning  is  very  much  quicker 
than  learning  of  nonsense  syllables,  and  that  the  material 
is  much  more  slowly  forgotten.  Most  learning  is  of  ideas, 
and  ideas  follow  logical  laws,  —  are  learned  in  connection 
with  principles  already  known  rather  than  by  the  bare  laws 
of  association.  In  consequence,  the  usual  learning  is 
much  quicker  and  forgetting  much  slower  than  the  results 
obtained  from  experiments  on  nonsense  syllables  in- 
dicate. The  other  laws  would  hold  with  slight  change ; 
in  fact  most  of  them  have  been  demonstrated  for  sense 
material.  The  one  difference  is  that  what  is  essential 
in  logical  learning  is  the  formation  of  associations  be- 
tween the  new  and  the  general  principles  that  explain 
them,  rather  than  the  formation  of  associations  between 
successive  elements. 

Evidence  for  the  advantages  of  logical  learning  and  the 
importance  of  the  background  of  organised  knowledge 
may  be  obtained  from  a  study  of  the  decay  of  memory. 
The  more  general  ideas  and  those  earliest  acquired  are 
always  the  last  to  be  lost.  The  aged  remember  the  events 
of  childhood  and  general  principles  long  after  recent 
events  and  particular  events  have  been  forgotten.  In 
brain  diseases  of  different  origins  the  same  laws  hold. 
Common  nouns  are  remembered  after  proper  names  are 
forgotten;  verbs  are  remembered  longer  than  nouns, 
and  gestures  persist  when  words  have  been  forgotten, 


206  ESSENTIALS   OF   PSYCHOLOGY 

The  reason  may  be  found  in  the  greater  chance  for  the 
general  terms  to  grow  into  the  nervous  system.  The 
general  terms  and  general  principles  have  been  used 
hundreds  of  times  where  particular  words  are  used  once, 
and  each  use  makes  the  impression  stronger,  and  makes 
possible  recall  on  new  occasions.  The  same  factors  that 
make  these  fundamental  principles  useful  and  perma- 
nent in  the  memory  of  the  normal  individual  make  them 
last  to  disappear  with  the  degeneration  of  nervous  tissue 
in  disease  and  old  age. 

Not  only  the  methods  of  remembering,  but  the  content 
of  the  memory  image,  are  different  in  logical  memory. 
One  thinks  of  remembering  as  a  process  of  reinstating 
the  original  experience  in  its  original  form.  As  a  matter 
of  fact,  however,  one  does  not  ordinarily  have  the  same 
sort  of  image  as  before ;  in  fact,  the  image  may  not  be 
at  all  like  the  original;  it  merely  means  the  same  thing. 
The  image  is  modified  by  all  that  has  been  seen  in  that 
connection  since  the  original  experience.  One  nearly 
always  remembers  the  event,  not  as  it  actually  was,  but 
as  it  must  have  been  in  the  light  of  what  has  been  ex- 
perienced before  and  after.  One  interprets  the  experi- 
ence in  terms  of  the  system  of  knowledge,  and  the  system 
modifies  the  images  that  are  recalled.  Reasoning  and 
memory  combine  in  the  construction  of  the  recalled  image. 
Still  more  frequently,  no  very  specific  image  is  reinstated; 
one  remembers,  not  the  event  itself,  but  that  the  event 
happened.  The  imagery  involved  in  remembering  that 
a  thing  happened  is  perhaps  some  symbol  of  the  event, 
or  some  general  symbol  plus  the  associations  that  connect 
it  with  z  specific  time ;  the  image  is  lost  in  its  meaning, 


MEMORY  AND   IMAGINATION  2O7 

in  the  fact  that  it  represents.  The  image  itself  is  not 
attended  to,  and  one  cannot  say,  after  the  experience 
has  been  recalled,  what  the  image  was  in  itself.  This 
sort  of  recall  is  closely  related  to  reasoning,  and  the  pro- 
cess can  be  understood  better  after  the  discussion  of 
meaning  in  the  next  chapter.  Suffice  it  now  to  say  that 
the  memory  is  usually,  not  of  images,  but  of  meanings. 
Recognition.  —  After  recall  comes  recognition.  Rec- 
ognition may  be  denned  as  an  awareness  of  the  time  and 
place  of  the  origin  of  the  memory  image.  Both  objects 
and  ideas  are  recognised,  and  recognised  in  the  same  way. 
One  meets  a  friend  of  earlier  years,  and  immediately  or 
after  some  thought  can  refer  him  to  a  definite  place  and 
to  a  definite  time  in  the  past.  Similarly  an  idea  may 
float  into  memory  and  either  be  recognised  as  a  fact  read 
in  a  school  book,  or  be  referred  vaguely  to  the  past  with- 
out specific  knowledge  of  its  warrant  or  of  its  authority. 
The  explanation  of  recognition  is  the  same  for  ideas  and 
for  objects.  The  process  can  be  studied  most  easily  in 
connection  with  the  delayed  or  indirect  recognition.  One 
frequently  sees  an  object,  and  is  at  first  uncertain  where 
it  has  been  seen  before  or  what  it  is.  Gradually  other 
ideas  cluster  about  it.  As  the  new  object  suggests  old 
ones,  the  new  begins  to  seemiamiliar,  and  finally  is  com- 
pletely recognised.  Then  it  takes  its  place  with  the  ideas 
that  have  themselves  been  recognised.  One  may  see  an 
animal  and  feel  that  it  is  of  a  familiar  species,  but  not 
remember  what  it  is.  The  object  suggests  a  setting  in 
which  it  was  seen  before,  and  that  may  suggest  the  name 
that  a  friend  gave  it  at  the  time,  or  the  picture  of '  the 
animal  in  the  volume  in  which  it  was  looked  up  after  it 


208  ESSENTIALS   OF   PSYCHOLOGY 

had  been  seen.  A  face  may  be  recognised  in  the  same 
way.  The  face  seems  familiar,  but  the  name  cannot  be 
given  nor  the  place  where  it  was  seen.  Gradually  a  cluster 
of  memories  group  about  the  face,  —  the  background  of 
a  familiar  room  where  the  man  was  seen,  or  the  class  room 
where  he  had  been  sitting;  then  the  name  or  other 
explanatory  ideas  may  come  up,  and  recognition  is  com- 
plete. In  general,  then,  this  delayed  or  immediate  rec- 
ognition is  always  due  to  associates  that  are  aroused  by 
the  object  or  idea,  when  it  presents  itself  to  Consciousness. 
When  recognition  is  immediate,  one  knows  at  once  that 
the  object  is  familiar,  there  is  no  evidence  of  the  nature 
of  the  process.  The  idea  or  thing  is  known  to  be  what 
it  is  at  once,  and  that  is  all  there  is  to  it.  This  is  the 
more  usual  sort  of  recognition.  One  knows  nothing  of 
how  a  close  friend  is  recognised,  or  how  one  tells  his  own 
text-book  from  his  neighbour's.  It  is  pretty  clear  from 
experiment  and  observation  that  the  process  is  in  part 
the  same  as  in  mediate  and  delayed  recognition.  As- 
sociates are  aroused  as  before,  but  they  come  at  once  and 
do  not  attract  attention  for  themselves.  They  give  evi- 
dence of  their  presence  only  by  the  fact  that  the  object 
is  recognised.  When  the  very  familiar  object  presents 
itself,  there  is  a  rush  of  associates,  or  the  opening  of  a  num- 
ber of  association  paths  that  bring  the  recognition  with 
them.  To  the  rush  of  associates  one  may  undoubtedly 
add  a  number  of  movements  that  are  called  out  reflexly. 
One  knows  one's  own  fountain-pen  by  the  fact  that  the 
movements  that  it  excites  are  suited  to  the  pen ;  there 
is  no  hesitation  or  false  adjustment.  When  a  friend's 
pen  has  been  picked  up  by  mistake,  one  becomes  aware 


MEMORY   AND   IMAGINATION  2OQ 

of  the  mistake  by  the  awkwardness  of  the  movements. 
The  finger  movements,  that  are  best  for  the  familiar 
pen,  make  the  new  one  scratch,  or  it  fails  in  some  other 
way  to  respond  as  the  old  one  does.  Part  of  the  recogni- 
tion of  an  object  that  is  not  handled  or  that  does  not  give 
rise  directly  to  movements  is  due  to  the  fact  that  its 
uses  are  appreciated,  that  when  it  is  recognised,  one 
knows  at  once  what  to  do  with  it  and  how  to  use  it.  As 
a  result  of  the  associates  and  of  the  smoothness  in  the 
actual  and  the  intended  or  possible  movements,  the  old 
object  ordinarily  arouses  a  feeling  of  pleasure,  while  the 
unfamiliar  is  nearly  always  unpleasant.  Possibly  one 
may  assume  a  peculiar  feeling  of  recognition  in  addition 
to  the  pleasure,  but  this  is  less  easy  to  be  sure  of  than  the 
fact  of  recognition. 

Three  factors  contribute  to  the  process  of  recognition. 
First,  the  arousal  of  associates;  second,  the  excitation  of  fa- 
miliar movements ;  third,  pleasantness,  —  a  result  of  these 
two  processes.  One  question  that  is  at  once  suggested 
in  this  connection  is  why  the  arousal  of  old  associates 
should  tell  what  the  object  is  and  where  it  was  seen  before. 
Part  of  the  answer  is  found  in  the  fact  that  the  associates 
themselves  are  recognised.  If  each  associate  is  recognised 
by  other  associates,  the  process  becomes  interminable  or 
compels  one  to  run  through  the  experiences  of  the  in- 
dividual from  the  time  of  the  event  recognised  to  the 
present  moment.  This  is  evidently  never  necessary; 
at  most  one  or  two  sets  of  associates  suffice  for  complete 
recognition.  The  reason  is  that  we  make  use  of  the  sys- 
tem of  knowledge  in  recognition  as  in  learning  and  re- 
tention. One  refers  the  new  to  the  developed  system. 


210  ESSENTIALS    OF    PSYCHOLOGY 

When  the  new  arouses  an  elernent  of  this  system,  rec- 
ognition is  complete.  In  other  instances  what  we  call 
recognition  is  nothing  more  than  reference  of  the  new 
thing  to  a  general  class.  We  recognise  a  small  animal  as 
a  weasel  when  we  can  classify  it ;  there  is  no  implication 
that  it  has  ever  been  seen  before.  This  classification  is 
only  a  reference  to  our  system  of  zoological  knowledge. 
Similarly  prominent  events  in  life  constitute  a  frame- 
work for  the  recognition  of  new  events.  These  may  be 
the  places  in  which  one  has  lived,  or  the  different  stages 
in  the  school  life  that  serve  for  the  recognition  of  personal 
events  as  do  the  kings  of  England  as  points  of  reference 
for  all  other  historical  events  for  the  later  history,  or  the 
succession  of  reigns  in  Rome  for  ancient  history.  Any 
event  is  placed  when  it  is  known  to  have  been  related  to 
or  contemporaneous  with  one  of  these  landmarks.  To 
understand,  and  to  recognise  in  this  way  are  very  closely 
related  operations.  Each  consists  in  being  referred  to 
the  framework  of  knowledge  or  to  the  system  of  prom- 
inent events. 

Paramnesia.  —  Paramnesia,  an  interesting  illusion  of 
recognition,  throws  much  light  upon  the  nature  of  rec- 
ognition. One  occasionally  feels,  when  in  a  new  place, 
that  one  has  been  there  before.  The  whole  setting  and 
many  of  the  details  of  the  place  are  familiar,  yet  one  is 
certain  that  this  is  the  first  visit.  Plato  described  the 
experience  and  used  it  in  support  of  his  theory  of  the 
transmigration  of  souls.  He  argued  that  the  recognition 
indicated  that  the  place  had  been  visited  in  an  earlier  ex- 
istence. As  a  matter  of  fact,  however,  the  explanation 
is  to  be  found  in  a  misplaced  recognition.  Some  parts 


MEMORY   AND   IMAGINATION  211 

of  the  situation  are  similar  to  old  situations.  These 
serve  to  arouse  associates  which  give  rise  to  a  feeling  of 
familiarity,  and  this  feeling  extends  from  the  part  to  the 
whole.  The  illusion  illustrates  the  dependence  of  rec- 
ognition upon  association  and  related  psychological 
processes.  The  old  is  not  recognised  where  these  pro- 
cesses are  lacking,  and  the  new  seems  familiar  when  by 
chance  these  processes  are  called  out  where  they  do  not 
belong. 

The  Best  Methods  of  Remembering.  —  Since  the 
ancients  much  speculation  has  been  indulged  in  about 
finding  easy  and  certain  ways  of  learning  and  remember- 
ing, and  in  all  ages  there  have  been  individuals  who  pro- 
fess to  have  methods  for  improving  the  memory.  All 
of  these  attempt  to  make  use  of  special  methods  in  form- 
ing associations.  They  fall  into  two  general  classes,  — 
methods  of  learning  single  things  such  as  dates,  and 
methods  of  connecting  two  facts  or  events  that  it  is 
desirable  to  remember  together.  Systems  for  remember- 
ing single  events  attempt  to  connect  them  with  symbols 
that  will  be  more  easily  remembered.  Numbers  are 
remembered  by  representing  each  digit  by  several  con- 
sonants and  then  making  words  that  include  these  con- 
sonants. Thus  if  b  or  c  represents  i ;  k,  I,  or  m,  5  ;  p  or 
r,  7  ;  and  s  or  t,  8 ;  1587  would  be  symbolised  by '  cloister.' 
Similar  combinations  could  be  made  to  represent  any 
date  or  number,  and  the  word  is  easier  to  remember  than 
the  number.  Where  two  events  are  to  be  connected  in 
memory,  it  is  possible  to  form  nonsense  or  superficial 
connections  between  them  that  shall  serve  to  recall  one 
when  the  other  is  given.  In  one  system  it  is  suggested 


212          ESSENTIALS  OF  PSYCHOLOGY 

that  one  may  remember  that  tete  in  French  means  '  head,' 
by  connecting  tele  with  '  potato  ' ;  that  in  turn  with 
'  root,'  since  potatoes  are  roots,  and  this  by  contrast  with 
'  head.'  Similar  series  of  words  are  suggested  for  many 
other  pairs,  and  the  system  consists  in  forming  them  for 
all  series  of  facts.  It  is  certain,  however,  that  when  used 
extensively,  any  such  system  requires  more  effort  and  is 
less  satisfactory  than  the  ordinary  forms  of  learning. 
There  is  some  advantage  in  mnemonic  verses  and  similar 
devices  in  remembering  a  few  purely  arbitrary  facts,  such 
as  the  number  of  days  in  the  months,  but  the  usefulness 
of  the  system  does  not  extend  far. 

The  best  mnemonic  system  is  the  ordinary  logical 
system  of  classification.  The  connections  are  not  ar- 
bitrary here,  and  each  series  of  associates  holds  not  for 
one  fact  alone  but  for  very  many.  In  one  sense,  the  classi- 
fications of  the  sciences  are  parts  of  a  vast  mnemonic 
system.  Each  general  principle  groups  many  facts  about 
a  single  statement.  Since  the  general  principles  are  them- 
selves more  or  less  closely  connected,  they  amount  in 
practice  to  a  system  of  associations  in  which  a  few  things, 
if  they  are  remembered,  will  serve  to  recall  all  the  know- 
ledge of  the  individual.  As  we  have  seen,  this  system  of 
knowledge,  when  it  has  been  developed,  makes  easier  the 
learning  of  all  things  that  are  referred  to  it,  makes  their 
retention  more  permanent,  and  serves  to  give  them  a  place, 
to  recognise  them  when  they  present  themselves  in 
memory.  It  follows  that  the  more  one  knows,  the  easier 
it  is  to  remember ;  and  the  more  one  knows  of  any  sub- 
ject, the  easier  it  is  to  learn  new  facts  in  that  subject. 
Much  better,  then,  than  any  artificial  memory  system 


MEMORY  AND   IMAGINATION  213 

is  a  patient,  thorough  learning  and  logical  classification 
of  facts.  This  not  only  makes  easy  the  learning  and  re- 
tention of  the  fact  in  question,  but  prepares  for  the  ac- 
quisition of  related  facts.  Learning  logically  is  like  put- 
ting money  at  compound  interest.  The  material  is  not 
only  saved,  but  grows  and  makes  easier  further  acquisi- 
tion. 

Memory,  then,  is  not  a  faculty  but  a  fact;  and  on 
analysis  it  is  found  to  be,  not  one  fact  or  process,  but  four 
that  together  make  possible  the  reinstatement  and  use 
of  earlier  experiences.  Learning,  retention,  recall,  and 
recognition  are  special  parts  and  uses  of  the  laws  of  as- 
sociation, and  of  the  interaction  between  the  particular 
new  events  and  the  earlier  accumulated  and  systematised 
knowledge.  Although  the  fundamental  principles  of 
memory  are  found  in  the  laws  of  association,  special 
methods  may  be  used  to  the  advantage  of  learning,  re- 
tention, and  recall.  But  above  all  special  methods  stands 
the  one  general  principle  that  memory  at  each  stage  re- 
quires constant  reference  to  systematised  knowledge. 
This  makes  learning  easy  and  rapid,  gives  permanent 
retention,  assures  recall  on  the  appropriate  occasion,  and 
provides  the  essential  conditions  for  recognition. 

Imagination.  —  We  have  left  over  a  series  of  revived 
mental  processes  that  occupies  a  relatively  large  place  in 
popular  and  scientific  discussion,  —  the  operations  that  are 
grouped  under  the  term  imagination.  Imagination  is 
like  memory  in  that  it  is  a  rearousal  of  earlier  experiences. 
It  is  like  it,  too,  in  that  the  revival  of  these  states  is  due 
to  the  laws  of  association.  It  differs  from  memory  in 
that  the  elementary  experiences  are  not  "aroused  in  the 


214  ESSENTIALS   OF  PSYCHOLOGY 

same  connections  or  groups  as  in  the  original.  The 
products  of  imagination  are  not  recognised ;  it  is  assumed 
on  the  contrary  that  the  things  we  imagine  have  no  real 
existence.  Elements  are  taken  from  various  things 
actually  seen  and  are  combined  in  new  ways  to  produce 
new  things.  All  the  thinking  operations  that  do  not  fall 
under  memory  or  reasoning  are  included  under  the  term. 
Imagination  is  classed  as  productive  or  reproductive  accord- 
ing as  it  is  more  like  reasoning  or  memory.  Constructive 
imagination  is  also  used  as  approximately  synonymous 
with  reasoning.  The  different  terms  are  used  rather 
loosely  and  it  is  hardly  worth  while  to  attempt  a  rigid 
definition.  It  is  not  necessary  to  say  more  of  the  de- 
termination of  imagination  than  that  it  follows  the-  laws 
of  association  under  the  influence  of  context  and  the 
other  wider  subjective  controls.  What  shall  be  imagined 
at  any  moment  depends  upon  the  preceding  thought,  the 
associations  that  have  been  formed,  and  the  purpose  or 
attitude  at  that  moment.  Imagination  is  characterised 
rather  by  the  degree  in  which  the  results  are  accepted 
as  true  or  familiar  than  by  the  way  the  results  are 
obtained.  This  needs  no  particular  discussion  other 
than  what  must  be  given  it  in  connection  with  memory 
and  reasoning. 

EXERCISES 

1.  Select  two  bits  of  verse  of  eight  lines  each  as  much  alike  as  pos- 
sible in  metre,  ease  of  learning,  etc.     Learn  one  at  one  sitting,  keep- 
ing a  record  of  the  number  of  repetitions  and  the  time  required  for 
learning.     Read  the  second  through  twice  each  day  until  it  is 
learned.     Which  method  is  the  more  economical  ? 

2.  Choose  two  other  selections  of  eight  lines.     Learn  the  first  as 


MEMORY  AND   IMAGINATION  215 

you  naturally  would,  or  two  lines  at  a  time.  Learn  the  second  by 
reading  through  from  beginning  to  end.  Compare  the  two  results 
for  the  time  and  number  of  repetitions  required.  Unless  the  selec- 
tions are  well  chosen,  it  may  be  necessary  to  repeat  the  experiment 
several  times  and  average  before  positive  results  are  obtained. 

3.  Relearn  two  bits  of  verse  that  were  originally  learned  by  the 
same  method  in  the  preceding  experiments,  one  after  twenty-four 
hours,  the  other  after  forty-eight  hours.     Compare  the  number  of 
repetitions  required  for  relearning  in  each  case,  with  the  number 
required  for  the  original  learning.     How  can  you  measure  the  rate 
of  forgetting  from  these  results  ? 

4.  Why  is  cramming  a  bad  method  of  study  ?    Answer  in  the  light 
of  the  laws  of  learning  and  forgetting. 

5.  What  rules  should  be  observed  in  studying  to  make  probable  a 
satisfactory  recitation  ? 

6.  How  does  the  ordinary  recitation  by  question  and  answer  illus- 
trate the  laws  of  recall  ?    What  is  the  question  and  what  the  answer 
in  the  terminology  of  memory?     Give  some  conditions  that  may 
make  a  good  recitation  impossible,  even  if  the  answer  to  the  question 
is  known. 

7.  Trace  the  course  of  recognition  in  some  instance  in  which  recog- 
nition is  delayed.     Why  should  the  mental  operations  that  result 
make  the  object  seem  familiar  ? 

8.  What  rules  suggest  themselves  for  acquiring  a  good  memory  ? 
What  are  the  limitations  of  the  rules  ? 


REFERENCES 

WATT  :  Economy  of  Memory. 

JAMES  :  Principles  of  Psychology,  vol.  i,  ch.  xvi. 

PILLSBURY  :  Attention,  chapter  ix. 

TITCHENER:  Text-Book  of  Psychology,  pp.  403-427. 

MEUMANN  :  Oconomie  und  Technik  des  Gedachtnisses. 


CHAPTER  IX 
REASONING 

REASONING  has  always  been  given  a  very  prominent 
place  among  mental  operations.  To  be  able  to  reason  is 
generally  recognised  as  the  mark  of  a  high  degree  of  in- 
telligence, and  to  reason  well  is  one  of  the  most  certain 
marks  of  exceptional  mental  development.  The  effec- 
tiveness of  a  man's  reasoning  measures  in  large  degree  his 
value  to  society,  and  his  own  possibilities  of  success.  It 
has  frequently  been  asserted  that  reason  is  peculiarly 
a  human  endowment.  Wundt,  for  example,  asserts  that 
animals  never  reason  and  man  seldom.  If  reasoning 
occupies  this  high  place  in  the  scale  of  human  capacities, 
it  is  evidently  desirable  to  know  what  distinguishes  it 
from  the  other  mental  operations  and  so  far  as  is  possible 
to  determine  the  laws  that  make  for  accurate  and  true 
reasoning.  The  definitions  of  reasoning  show  much  di- 
versity. A  very  simple  definition  is  that  reasoning  is 
purposive  thinking.  But  to  constitute  reasoning,  think- 
ing must  be  not  only  purposive,  i.e.  must  not  only  have 
a  definite  end,  but  must  also  be  true  and  be  able  to  justify 
itself.  Reasoning  is  a  process  of  solving  problems.  The 
solution  of  the  problem  must  be  true,  and  must  also  be 
proved.  To  define  reasoning  fully,  it  must  be  dis- 
tinguished from  imagination  and  memory  when  observed 
from  the  inside,  and  from  instinct  and  habit  when  ex- 
pressed in  action. 

216 


REASONING  217 

Reasoning  Distinguished  from  other  Mental  Processes. 

—  Reasoning  may  be  distinguished  from  memory  and 
imagination,  not  so  much  by  the  character  of  the  mental 
states  or  by  the  way  that  they  are  obtained,  as  by  the 
attitude  that  is  taken  toward  them  when  they  .arise. 
The  idea  that  is  attained  by  reasoning  may  be  exactly  like 
an  idea  that  on  other  occasions  or  by  another  man  is 
merely  remembered.  The  laws  that  govern  the  ap- 
pearance of  rational  ideas  are  the  laws  of  association, 
controlled  in  the  same  way  as  in  memory  or  imagination. 
The  important  differences  are:  that  the  results  of 
reasoning  are  new  and  are  accepted  as  true ;  the  results 
of  memory  are  true,  but  not  new;  and  the  results  of 
imagination  are  new,  but  not  true.  Belief  is  the  process 
of  accepting  a  construction  as  true,  and  may  be  said  to 
hold  the  same  relation  to  reasoning  that  recognition  does 
to  memory.  When  an  idea  is  recognised  and  believed,  it 
is  remembered ;  when  believed,  but  not-  recognised,  it 
is  the  result  of  reasoning;  and  when  neither  recognised 
nor  believed,  it  is  imagined.  The  distinction  may  be 
illustrated  by  the  different  ways  of  preparing  a  lesson  in 
geometry.  One  student  merely  commits  the  demonstra- 
tions and  when  called  upon  to  recite  repeats  by  rote  the 
words  of  the  book.  Another  does  not  commit  to  memory 
but  reads  over  and  understands  each  point  made.  When 
called  upon  to  recite,  he  works  out  the  problem  for  him- 
self in  large  measure,  following  only  the  general  lines  of 
the  book.  He  has  made,  not  the  words,  but  the  ideas 
his  own  and  is  able  to  make  new  applications  of  the 
method  when  called  upon  to  do  so.  He  believes  in  his  re- 
sult because  he  can  see  that  it  fits  into  the  other  proposi- 


21 8  ESSENTIALS   OF   PSYCHOLOGY 

tions  he  has  developed  in  the  subject  and  with  other 
things  that  he  knows,  but  he  does  not  recognise  the 
conclusion  or  the  construction  when  it  develops  in  his 
mind. 

If  one  were  watching  the  actions  of  a  man  or  animal 
and  knew  nothing  of  the  thinking  processes  behind  them, 
one  would  still  decide  on  certain  occasions  that  the  indi- 
vidual was  reasoning,  and  on  other  occasions  that  he  was 
acting  from  habit  or  instinct,  or  from  mere  chance  re- 
sponses. As  compared  with  habit  or  instinct,  reasoned 
actions  must  be  new,  —  this  must  be  the  first  occasion  on 
which  the  movement  has  been  made:  as  opposed  to 
mere  chance  response,  the  reasoned  movement  is  repeated 
unfailingly,  and  is  not  preceded  by  other  responses. 
Lloyd  Morgan  illustrates  the  difference  by  the  way  his 
dog  learned  to  carry  a  stick  through  a  picket  fence.  His 
habits  and  instinct  led  him  to  pick  it  up  by  the  middle. 
Of  course  it  caught  at  both  ends  on  the  pickets.  Only 
after  many  trials  did  he  happen  to  hit  upon  seizing  it  by 
the  end  and  thus  succeed  in  dragging  it  through.  If  he 
had  reasoned,  he  would  have  appreciated  the  impossi- 
bility of  his  first  attempt  without  trial,  or  at  the  first  trial. 
The  trials  would  have  been  made  in  thought  only,  and 
action  would  not  have  been  attempted  until  the  problem 
had  been  solved  mentally.  Then  one  act  would  have 
been  all  that  was  necessary.  Possibly,  one  would  accept 
as  reasoning  an  act  that  gives  an  adequate  solution  of  a 
new  problem,  when  no  solution  in  thought  preceded  the 
act.  On  this  the  definitions  divide.  If  one  does  include 
acts  of  this  sort  under  reasoning,  it  would  follow  that  ani- 
mals reason ;  if  reasoning  is  always  a  matter  of  thought 


REASONING  2 19 

or  first  a  matter  of  thought,  then  reasoning  cannot  with 
certainty  be  ascribed  to  animals. 

One  further  step  is  often  present  in  reasoning  and  by 
some  is  made  essential  to  the  definition.  This  is  justify- 
ing the  conclusion  before  it  has  been  tried  in  practice. 
This  is  certainly  not  present  in  animals  and  most  of 
what  is  ordinarily  called  reasoning  in  man  has  no  explicit 
justification.  Reasoning  has  also  been  restricted  to 
thinking  in  general  terms.  While  much  of  human  reason- 
ing is  general,  it  would  unwarrantably  limit  the  term  to 
exclude  all  instances  of  solving  particular  problems.  If 
we  bring  together  the  characteristics  of  reasoning,  we 
may  say  that  it  is  a  mental  operation  that  (i)  is  directed 
to  the  solution  of  a  problem,  is  purposive,  not  random ; 
(2)  the  results  of  the  thinking  must  be  a  new  solution  that 
is  accepted  as  true ;  (3)  the  action  to  which  the  thinking 
leads  must  also  be  new  and  immediately  adequate ; 

(4)  the  solution  may  be  warranted,  in  advance  of  test,  by 
reference  to  general  principles  or  earlier  experiences ;  and 

(5)  the  solution  itself  may  be  general,  i.e.  applicable  to 
many  situations,  or  it  may  be  particular.     The  two  most 
important  new  principles  involved  in  reasoning  are  the 
.acceptance  of  the  conclusion  as  true  and  thinking  in  gen- 
eral terms. 

Belief  the  Test  of  Truth.  —  The  simplest  answer  to 
the  question,  what  is  true,  is  that  what  is  true  for  the  in- 
dividual is  what  he  is  willing  or  able  to  believe.  The 
simplest  answer  to  the  next  logical  question,  what  he  be- 
lieves, is  that  he  believes  any  thing. that  is  in  full  harmony 
with  his  experience.  Ordinarily  there  is  immediate  re- 
jection of  any  statement  that  is  not  consistent  with  one's 


22O  ESSENTIALS    OF   PSYCHOLOGY 

previous  experience.  Just  as  the  normal  man  rejects  an 
hallucinatory  impression  because  it  is  in  contradiction  to 
the  conditions  of  his  seeing  and  will  not  fit  into  his  idea 
of  the  world,  so  a  statement  or  conclusion  that  is  out  of 
harmony  with  the  earlier  knowledge  is  refused  belief. 
The  general  rule  is  that  one  believes  when  there  is  no 
reason  to  doubt,  when  there  is  no  conflict  between  new 
and  old.  The  older  experiences  stand  guard  in  the 
reasoning  operations  as  in  all  mental  operations,  and 
when  any  construction  does  not  agree  with  them,  the 
unpleasant  feeling  of  doubt  arises  as  a  bar  to  its  ac- 
ceptance. Many  constructions  pass  without  question, 
but  when  one  is  doubted,  it  must  then  be  formally 
proved  or  given  up  as  untrue.  Doubt  is  the  incentive 
to  all  of  the  formal  reasoning  processes,  while  belief 
makes  them  unnecessary. 

Meaning  and  the  Concept.  —  One  of  the  most  striking 
facts  in  connection  with  reasoning  is  that  the  images  em- 
ployed are  not  important  for  themselves,  but  only  for 
their  meaning,  for  the  things  that  they  represent.  In  a 
demonstration  in  geometry,  for  example,  the  figure  rep- 
resents all  objects  of  similar  form,  without  reference  to 
their  size  or  the  materials  from  which  they  are  made. 
The  statements  will  hold  of  pieces  of  paper  or  tracts  of 
land,  just  as  truly  as  "of  the  figure  drawn  in  chalk  or  pencil. 
In  all  reasoning  the  same  phenomenon  is  observed. 
When  one  plans  a  house,  one  thinks  of  lumber  and  of  stone, 
but  not  of  any  particular  boards  or  stones ;  or,  if  one  does 
think  of  a  particular  material,  it  is  recognised  that  any- 
thing else  of  the  sort  may  be  substituted  for  it  without  in- 
jury to  the  plans.  The  image  in  question  does  duty  for  or 


REASONING  221 

represents  all  other  articles  of  the  same  kind.  An  image 
that  is  used  in  this  way  to  represent  other  things  is  called 
a  concept,  and  the  things  that  it  represents  at  the  moment 
constitute  its-  meaning.  Two  questions  naturally  arise 
with  reference  to  this  representative  function,  (i)  How 
is  it  possible  for  a  single  concrete  image  to  represent  so 
many  different  objects  in  thought  ?  This  is  the  problem 
of  meaning.  (2)  What  is  the  character  of  the  imagery 
that  represents  the  numerous  particulars  ?  This  is  the 
historical  problem  of  the  nature  of  the  concept. 

Meaning  involves  the  Principles  of  Recognition.  — 
The  representative  function  of  images  is  more  closely  re- 
lated to  the  function  of  recognition  than  to  any  of  the 
other  principles  that  have  been  hitherto  discussed. 
When  an  object  is  perceived,  it  takes  its  value  from  the 
earlier  connections  in  which  it  has  been  seen.  If  the  ob- 
ject is  not  at  once  recognised,  it  will  ordinarily  soon  recall 
other  objects  that  are  familiar.  The  process  of  recog- 
nition was  seen  to  be  due  in  last  analysis  to  partially  or 
completely  aroused  associations.  When  the  object  is  not 
recognised  as  a  particular  object  or  as  an  object  that  has 
been  seen  in  some  particular  place,  it  may  still  be  appre- 
ciated as  a  member  of  a  class.  I  recognise  a  bird  in  flight 
as  a  robin,  but  not  as  the  robin  that  has  its  nest  on  my 
lawn ;  I  recognise  a  tool  as  a  hammer,  but  not  as  my  ham- 
mer that  has  been  missing  since  last  week.  This  class 
recognition  is  sometimes  called  cognition,  but  it  follows 
the  same  general  laws  as  recognition.  It,  too,  is  depend- 
ent upon  the  connections  that  have  been  formed  betw  een 
many  objects  and  one  single  name  or  type.  It  is  due  to 
the  arousal  of  old  situations  in  which  similar  objects  have 


222  ESSENTIALS    OF   PSYCHOLOGY 

been  experienced,  and  of  old  uses  to  which  they  have  been 
put.  These  associates  prepare  one  to  deal  with  the  ob- 
ject when  presented,  and  give  it  a  peculiar  conscious 
quality,  a  quality  that  changes  with  its  classification. 

The  representative  function  of  the  image  has  the  same 
explanation.  When  the  image  presents  itself,  it  has  a 
constellation  of  associations  about  it  and  these  give  it 
meaning.  These  associations  tend  to  recall  each  of  the  ob- 
jects represented  and  the  uses  to  which  each  has  been  put. 
These  association  paths,  partly  aroused,  make  the  image 
representative  of  each  object  and  of  each  use  intended. 
When  it  represents  a  single  object,  there  is  but  a  single 
associate  or  group  of  associates,  as  in  recognition  of  an 
object  as  individual;  when  it  represents  a  class,  many 
associates  are  partially  aroused,  as  in  the  recognition  of  an 
object  as  one  of  a  kind.  The  feeling  varies  with  the  as- 
sociates. Thinking  goes  on  as  if  all  the  associates  were  in 
consciousness,  instead  of  the  single  representative  image. 
As  the  recognition  of  the  object  depends  upon  the  asso- 
ciates that  are  partially  aroused  at  the  moment,  so  the 
meaning  of  the  image  is  the  expression  of  its  partially  or 
potentially  aroused  connections.  When  one  recognises 
a  man  as  a  man,  the  same  paths  are  aroused  as  when  one 
has  in  mind  a  particular  image  of  a  man  and  knows  that 
it  represents  all  men  of  whatever  kind. 

The  Concept. —  The  image  that  represents  the  par- 
ticulars, the  image  that  has  the  meaning,  is  known  as  the 
concept.  The  nature  of  the  concept  has  been  much  dis- 
cussed in  the  history  of  philosophy  and  psychology.  It 
has  been  argued  that  the  image,  which  has  a  general  mean- 
ing, must  itself  be  general  in  form.  Following  out  this  line 


REASONING  223 

of  reasoning,  it  has  been  asserted  that  the  image  of  gen- 
eral meaning  may  be  some  bare  outline  of  all  the  particu- 
lars that  it  represents,  or  that  it  may  be  a  composite 
picture  of  all.  My  image  of  a  dog  would  be  a  dog  with- 
out colour  or  particular  size  or  length  of  hair.  My  image  of 
a  man,  a  composite  photograph  of  all  the  men  I  had  ever 
seen.  In  any  case  it  would  be  an  image  that  was  like 
each  of  the  things  it  represents,  but  not  identical  with 
any  of  them.  This  sort  of  vague  schematic  image  some- 
times constitutes  the  concept,  but  it  is  not  at  all  universal. 
It  is  no  more  necessary  that  the  concept  be  represented 
by  a  general  image,  than  that  the  object  recognised  as 
some  sort  of  tool  shall  be  general  in  form.  What  gives 
each  its  generality  is  the  group  of  associates  that  cluster 
about  it.  In  fact,  the  two  most  usual  images  of  general 
meaning  are,  on  the  one  hand,  an  individual  object  that  has 
nothing  of  the  general  in  its  make-up ;  on  the  other  hand, 
the  word,  which  is  not  at  all  like  any  of  the  things  repre- 
sented. When  one  thinks  man  in  general,  one  is  likely 
to  think  either  of  some  individual  who  is  familiar,  or 
merely  the  word  man.  Each  will  represent  perfectly  all 
men  or  all  human  qualities,  since  what  is  important  is  not 
the  imagery,  but  the  associates  that  are  aroused. 

The  individual  image  represents  the  different  particu- 
lars in  the  same  way  that  a  model  represents  the  different 
machines  that  may  be  manufactured  under  a  patent. 
The  model  may  be  of  wood,  while  the  machines  are  made 
of  different  metals ;  the  model  is  usually  small,  the  actual 
machines  are  large ;  and  numerous  other  changes  may  be 
made  in  the  model,  but  it  still  is  regarded  as  typical  of 
them.  Its  meaning,  like  the  meaning  of  the  concept,  is 


224          ESSENTIALS  OF  PSYCHOLOGY 

found  in  all  of  the  machines  that  might  be  built  on  its  lines. 
The  model  and  the  actual  machines  are  often  spoken  of  as 
embodying  the  same  idea,  in  spite  of  the  differences  in  size 
and  materials.  When  thus  associated  with  many  partic- 
ulars, an  individual  idea  stands  for  them  in  thought,  and 
the  results  of  the  thinking  hold  true  for  each  of  the  par- 
ticulars represented,  as  well  as  for  the  actual  image.  The. 
word,  too,  represents  objects  in  thinking  because  of  its 
many  associates.  When  the  word  is  thought,  the  asso- 
ciates are  aroused  and  colour  the  word,  so  that  it  seems  to  be 
not  a  mere  word,  but  something  much  more  real  and  vivid. 
The  difference  between  the  word  as  bare  image  and  as 
representative  of  objects  has  been  illustrated  by  James  by 
asking  one  to  stare  at  a  word  on  the  printed  page  for  a  few 
minutes  as  just  a  word.  After  one  has  looked  at  the  word 
in  this  way  for  a  short  time,  the  meanings  seem  to  drop 
away  and  the  word  image  alone  remains.  The  difference 
between  this  and  the  word  as  ordinarily  used  is  very  strik- 
ing, how  striking  one  can  discover  only  by  trying  the  ex- 
periment. In  general,  then,  the  image  that  is  the  centre 
of  the  concept  is  relatively  a  matter  of  indifference ;  what 
is  essential  is  the  associates  of  the  image.  The  meaning 
of  the  concept  changes  from  moment  to  moment  as  the 
connections  change.  Words  change  their  meanings  with 
the  context.  The  English  '  son '  and  the  French  son  have 
an  altogether  different  feeling.  The  reason  is  that  the 
associates,  that  are  partially  active,  change  as  the  context 
changes.  Everything  serves  to  emphasise  the  fact  that 
the  associates  which  irradiate  from  the  concept  are  the  im- 
portant part,  and  the  image  from  which  they  irradiate  is 
relatively  indifferent. 


REASONING  225 

The  Development  of  Concepts. — The  statement  that  the 
meaning  of  the  concept  depends  upon  the  associates  that 
have  been  formed  about  it  is  well  illustrated  by  the  way 
concepts  grow,  either  in  the  individual,  or  in  the  develop- 
ment of  knowledge  as  a  whole.  The  child's  knowledge 
grows  through  a  process  of  developing  and  changing  con- 
cepts. If  one  dare  speculate  on  the  nature  of  the  first 
experiences  of  the  child,  one  must  conclude  that  in  the 
beginning  all  is  chaos.  It  is  only  as  concepts  develop, 
about  which  the  experiences  may  cluster  and  to  which 
they  may  be  referred,  that  any  order  is  introduced. 
When,  for  example,  a  child  sees  a  kitten  for  the  first  time, 
there  are  no  concepts  to  which  it  may  be  referred,  and  the 
kitten  has  no  meaning  for  him.  It  is  a  mass  of  sensations, 
that  is  all.  Even  what  little  appreciation  there  is,  is  in 
terms  of  older  experiences  that  have  become  definitely 
established.  The  kitten  resembles  the  mother's  furs,  its 
colour  suggests  coal ;  each  of  its  other  qualities,  that  are 
appreciated  at  all,  are  appreciated  only  as  they  are  re- 
ferred to  known  qualities  and  objects.  When  the  kitten 
has  been  seen  a  few  times,  it  becomes  in  its  turn  a  centre 
of  reference  for  new  experiences.  At  first  it  will  stand  as 
the  type  for  all  animals ;  the  first  dog  seen  will  be  called 
'kitty'  and  any  other  animal  that  presents  itself  will  re- 
ceive the  same  greeting.  The  concept  of  the  cat  will 
develop  from  this  point  by  two  sorts  of  experiences. 
Each  new  kind  of  cat  will  increase  the  number  of  objects 
that  are  represented  by  the  term,  while  each  quality  of  the 
cat,  or  of  any  cat,  will  increase  the  qualities  that  may  be 
ascribed  to  the  animal.  When  the  animal  is  seen  to  eat, 
a  new  point  of  resemblance  to  man  is  indicated.  As  the 
Q 


226  ESSENTIALS   OF   PSYCHOLOGY 

college  student  studies  the  anatomy  and  physiology  of 
the  cat,  the  concept  is  deepened  and  extended  through  the 
relations  that  are  found  between  less  fully  developed  ani- 
mals, on  the  one  side,  and  chemical  and  physical  laws,  on 
the  other.  Each  of  these  experiences,  either  of  new  sorts 
of  cats  or  of  new  qualities  and  responses  of  cats,  serves  to 
extend  the  concept.  These  individuals  and  laws  and 
functions  are  all  represented  by  the  concept  in  thinking ; 
and  the  greater  the  number  of  connections  that  have  been 
developed  with  it,  the  wider  is  the  concept,  because  the 
greater  is  the  number  of  associates  that  are  partially 
aroused  when  the  image  is  called  to  mind.  The  concept 
is  the  point  of  reference  of  all  that  is  known  about  cats. 
The  development  of  concepts  in  the  race  is  even  more 
interesting,  and  the  development  can  be  traced  more 
completely.  Practically  all  of  our  important  ideas  are 
concepts.  One  of  the  most  used  is  the  system  of  numbers. 
As  the  word  '  digit '  shows,  counting  was  at  first  always 
on  the  fingers.  The  larger  groups,  five  and  ten,  are  the 
fingers  of  one  hand  and  of  two,  respectively.  Still  larger 
numbers  are  multiples  of  ten,  the  largest  number  that  can 
be  counted  on  the  fingers.  After  the  habit  of  referring  ob- 
jects to  the  fingers  in  counting  had  been  developed,  the 
reference  became  less  explicit,  and  finally  all  thought  of 
the  fingers  was  lost  from  the  number  idea.  The  number 
symbols  developed  and  were  capable  of  replacing  the 
finger  idea  altogether.  One  may  still  see  some  evidence 
of  the  fingers  in  the  Roman  numerals,  but  in  the  Arabic 
symbols  in  ordinary  use,  there  is  now  no  evidence  of  any 
similarity  to  the  fingers  or  to  anything  that  at  all  cor- 
responds to  the  values  that  are  represented.  The  num.- 


REASONING  227 

bers  gathered  many  associates,  and  each  new  sort  of  thing 
that  was  counted  served  to  make  the  concept  more  gen- 
eral in  its  application,  until  the  original  reference  and 
practically  all  imagery  disappeared  in  the  meaning  or 
idea.  One  can  trace  similar  stages  in  the  development 
of  any  sort  of  concept.  Words  of  abstract  meaning  were 
nearly  all  concrete  at  one  time.  The  meaning  first  be- 
came very  much  extended ;  then  some  one  meaning,  re- 
mote from  the  original,  became  emphasised,  and  the  origi- 
nal one  was  forgotten,  or  what  was  originally  the  name 
of  a  substance  or  thing  came  to  designate  an  abstract 
quality.  All  of  the  fundamental  ideas  of  science  could 
probably  be  traced  to  some  perfectly  concrete  object  or 
idea  that  gradually  has  been  applied  to  many  objects  and 
so  has  lost  all  particular  meaning.  The  atom,  molecule, 
ether,  force  itself  have  undoubtedly  had  this  sort  of 
origin.  Now  they  are  concepts  that  have  value  because 
they  represent  a  large  number  of  particular  experiences. 

Laying  aside  for  the  moment  the  problem  of  the  de- 
velopment of  the  concept,  one  may  assert  that  practically 
all  of  the  ordered  knowledge  of  any  individual  at  any 
moment  is  found  in  the  system  of  concepts.  The  system 
of  concepts  contains  not  merely  abstract  and  concrete 
things  like  atoms  and  ether,  tables  and  trees,  but  general 
.  laws  and  principles,  such  as  special  laws  of  connections 
and  the  principle  of  cause  and  effect.  All  that  one  knows 
finds  jts  place  in  the  system  of  concepts ;  the  system  of 
knowledge  and  the  system  of  concepts  are  practically 
identical  terms.  These  concepts  and  general  laws  have 
value,  (i)  because  they  are  types  and  are  in  consequence 
more  nearly  true  than  any  particular  experience  of  the 


228          ESSENTIALS  OF  PSYCHOLOGY 

class ;  (2)  they  represent  a  mass  of  particulars  by  virtue 
of  the  fact  that  each  of  the  particulars  has  been  asso- 
ciated with  the  concept,  and,  without  detriment  to  the 
truth  of  the  statement  that  is  made,  might  be  replaced 
by  any  one  of  the  particulars.  This  system  of  concepts 
plays  an  important  part  in  each  of  the  simpler  psycho- 
logical operations,  as  well  as  in  reasoning.  One  ordina- 
rily sees,  not  the  group  of  sensations,  but  the  developed 
type  or  concept  of  the  object.  Similarly  any  statement 
or  thing  can  be  remembered  much  more  easily  if  only  it 
can  be  connected  with  the  system  of  knowledge  already 
obtained.  Ordinarily  one  recognises  an  object  by  re- 
ferring it  to  the  class  to  which  it  belongs,  even  when  it 
may  be  recognised  also  as  a  particular  member  of  the 
class.  While  concepts  play  an  enormously  important 
part  in  each  of  these  mental  operations,  it  is  in  reasoning 
that  the  concept  attracts  most  attention.  Here  its  im- 
portance cannot  be  overstated.  Each  of  the  reasoning 
operations  involves  reference  to  the  system  of  concepts. 
The  situation  is  judged  by  referring  it  to  the  system  of 
knowledge,  and  to  its  particular  concept.  When  a  solu- 
tion has  been  reached,  it  is  justified  or  proved  by  a 
reference  to  the  appropriate  general  concept,  law,  or 
principle.  All  processes  of  understanding  and  of  proof, 
are  in  terms  of  the  classified  body  of  knowledge,  in  terms 
of  concepts. 

We  have  seen  that  the  reasoning  operation  is  ordinarily 
some  bit  of  purposive  thinking  that  is  capable  of  proof. 
Thinking  primarily  requires  that  one  have  a  purpose  and 
be  thwarted  in  that  purpose.  One  has  no  incentive  to  ac- 
complishment if  one  has  no  purpose,  and  no  new  opera- 


REASONING  2  29 

tions  are  demanded  if  the  old  habits  are  sufficient  to  effect 
the  purpose.  Reasoning  presupposes  a  thwarted  purpose 
as  its  starting  point.  Three  stages  in  the  reasoning  opera- 
tion may  be  distinguished.  First,  the  obstacle  must  be 
appreciated  or  understood ;  second,  some  plan  that  will 
remove  the  obstacle  must  be  developed;  and  third,  the 
plan  that  suggests  itself  must  be  proved,  must  be  justified. 
The  obstacle  may  block  the  progress,  either  of  thought 
or  action.  But  if  the  obstacle  be  to  thought  alone,  it  will 
probably  be  an  obstacle  to  action  at  some  time,  and  to 
remove  it  in  thought  will  make  action  easier  when  occa- 
sion arises.  The  first  of  these  steps,  the  process  of  under- 
standing the  difficulty,  is  judgment ;  the  second  is  infer- 
ence ;  and  the  third,  proof. 

One  may  illustrate  the  different  parts  of  the  process  by 
any  simple  problem.  Suppose  two  boys  are  canoeing,  and 
it  is  desired  to  reach  a  distant  place  in  a  limited  time. 
Suddenly  the  canoe  scrapes  hard  on  a  rock.  A  moment 
later  water  begins  to  rise  in  the  bottom.  At  first  it  is 
a  question  whether  there  is  a  leak  or  whether  the  water 
has  been  shipped.  As  it  increases  in  amount,  it  becomes 
evident  that  the  water  comes  fro.m  a  leak.  When  this 
is  decided  upon,  one  has  a  judgment,  a  classification  or 
interpretation  of  the  trouble.  Further  explanation  comes 
when  the  scraping  on  the  rock  is  recalled,  and  a  complete 
understanding  is  obtained  when  the  canoe  is  turned  up 
and  the  hole  through  the  canvas  is  discovered.  The 
next  step  is  to  decide  upon  a  remedy.  Someone  suggests 
that  a  patch  might  be  made  of  a  handkerchief.  This 
is  probably  rejected  as  soon  as  the  thinness  of  the  mate- 
rial is  recalled.  A  second  or  added  suggestion,  that  the 


230 


ESSENTIALS   OF   PSYCHOLOGY 


handkerchief  be  covered  with  pitch  from  a  spruce  tree 
on  the  shore,  is  accepted  by  both  and  put  to  the  test. 
Thinking  of  coating  the  handkerchief  with  pitch  consti- 
tutes the  inference.  Were  the  suggestion  of  using  pitch 
questioned  by  one,  and  successfully  defended  by  the  other, 
the  process  would  be  completed  in  proof.  Proof  conies 
only  when  there  is  preliminary  doubt  on  the  part  of  the 
man  who  makes  the  suggestion,  or  on  the  part  of  some- 
one who  hears  it.  Ordinarily  the  suggestion  will  be 
accepted  without  question.  It  will  be  believed  at  once 
and  at  once  be  put  into  practice.  The  test  will  be  met 
at  once  and  almost  unconsciously.  It  is  only  when  there 
is  doubt  before  the  test  is  made  that  one  requires  proof, 
and  the  full  reasoning  process  is  completed.  In  our  case, 
one  would  justify  the  use  of  pitch  on  the  handkerchief 
only  when  someone  asks  how  that  would  help.  Then 
the  justification  may  be  made  in  one  of  several  ways. 
One  may  answer  in  the  abstract  that  pitch  is  sticky  and 
waterproof,  or  one  may  recall  that  the  Indians  used  pitch 
in  repairing  or  making  canoes,  or  one  may  recall  his  own 
use  of  pitch  for  some  similar  purpose. 

Of  these  steps  in  the  reasoning  process,  judgment  and 
the  different  forms  of  proof  have  received  the  most  atten- 
tion, particularly  from  the  logician.  The  judgment 
may  be  defined  most  simply  as  the  process  of  referring 
a  new  situation  to  its  appropriate  concept,  or,  as  it  is 
more  usually  defined,  as  the  process  of  '  ascribing  meaning 
to  the  given.'  Each  difficulty  or  obstacle  has  a  different 
class  in  which  it  belongs ;  it  is  understood  in  terms  of  a 
different  sort  of  older  experience,  or  different  groups  of 
older  experiences.  Judgments  might  be  named  in  terms 


REASONING  23! 

of  the  different  sorts  of  classifications  that  are  made. 
There  are  judgments  of  things,  judgments  of  relation  in 
which  the  relations  are  referred  to  typical  relations, 
judgments  of  evaluation  in  which  the  objects  are  referred 
to  typical  standards,  etc.  It  is  more  usual  to  classify 
with  reference  to  the  assertion  that  is  made.  This  gives 
the  analytic  judgment  in  which  a  relatively  complex 
whole  is  referred  to  a  number  of  abstract  or  general 
qualities;  and  the  synthetic  judgment  in  which  the  given 
is  improved  or  changed  in  some  way  by  the  operation  of 
judgment. 

In  what  has  been  regarded  as  the  typical  judgment 
by  the  formal  logician,  the  process  of  reference  is  expressed 
in  words.  The  form  of  expression  is  undoubtedly  more 
variable  than  the  formal  logician  will  admit.  In  many 
cases,  perhaps  in  most  cases,  the  new  situation  is  repre- 
sented in  the  subject  of  the  sentence  or  the  proposition, 
and  the  general  concept  or  principle  to  which  it  is  referred 
is  put  in  the  predicate.  When  the  water  is  seen  to  appear 
in  the  bottom  of  the  canoe,  one  would  say  '  there  is 
a  leak/  in  which  the  '  there  '  represents  the  general 
situation ;  the  leak,  the  classification  of  the  situation  or 
difficulty.  The  particular  present  experience  is  stated  in 
the  subject ;  the  concept  that  interprets  it,  in  the  predi- 
cate. Under  the  head  of  judgment  are,  not  only  these 
interpretations  of  the  present  situations,  but  also  many 
possible  experiences  that  may  need  to  be  faced  for  the 
benefit  of  later  action  and  disposition.  Such  are  all  of 
the  descriptions  and  classifications  of  science,  and  all 
abstract  explanations  whatever.  Here,  too,  would  come 
all  classifications  of  phenomena  that  are  of  value  only  in 


232  ESSENTIALS   OF   PSYCHOLOGY 

enabling  one  to  understand  them.  From  one  point  of 
view  this  text  on  psychology  may  be  said  to  be  nothing 
more  than  a  series  of  references  of  the  mental  phenomena 
to  classes  and  laws  that  may  enable  one  to  know  what  to 
expect  in  the  future,  and  to  understand  the  thinking  of 
the  present  and  of  the  past.  All  understanding  is  a 
reference  of  the  thing  to  be  understood  to  the  system  of 
concepts ;  the  thing  to  be  understood  is  ordinarily  repre- 
sented in  speech  by  the  subject  of  the  judgment  or  of  the 
sentence,  and  the  concept  by  which  the  new  is  explained 
is  expressed  in  the  predicate.  What  for  the  psychologist 
is  a  reference  of  the  new  to  a  concept  is,  for  formal  logic 
and  grammar,  a  combination  of  words,  a  succession  of 
subject  and  predicate. 

Inference.  —  Inference  is  primarily  a  psychological 
process.  Ordinarily  one  solves  problems  by  casting 
around  until  the  proper  solution  suggests  itself.  The 
suggestion  follows  laws  of  association,  just  as  does  mem- 
ory or  imagination,  but  the  essence  of  the  reasoning  or 
inference  is  to  be  found,  not  so  much  in  the  way  the  sug- 
gestions come  up  as  in  the  way  they  are  treated  when  they 
come.  The  greater  the  fluidity  of  ideas,  the  greater  the 
number  of  suggestions  that  arise,  the  more  likely  is  the 
true  solution  of  the  problem  to  be  obtained.  The  essen- 
tial thing  is  that  the  true  solution  be  recognised  when  it 
appears,  and  that  all  false  suggestions  be  rejected.  If 
the  reader  will  observe  his  thinking  while  trying  to  solve 
a  problem  in  geometry,  or  while  trying  to  find  some  way 
to  earn  money  for  a  vacation,  or  in  any  other  problem, 
he  will  see  that  many  different  suggestions  present  them- 
selves before  one  is  found  that  is  accepted  as  a  probable 


REASONING  233 

solution.  The  problem  of  inference,  then,  falls  into  two 
distinct  parts:  first,  how  do  the  suggestions  arise? 
second,  how  are  the  true  suggestions  separated  from  the 
false  ?  The  answer  to  the  first  question  has  been  given 
in  the  chapter  on  association.  The  solution  in  reasoning 
is  called  up  by  the  connections  that  have  been  earlier 
established,  is  controlled  and  directed  by  the  purpose  of 
the  moment,  the  mental  context.  The  selection  of  the 
true  solution  is  in  terms  of  belief.  When  a  conclusion 
comes  that  is  in  harmony  with  all  that  is  known  on  the 
subject,  it  is  ordinarily  accepted  and  put  to  practical 
test.  When  the  suggestion  does  not  harmonise  with 
some  experience  that  is  definitely  in  consciousness  at  the 
moment,  it  is  immediately  rejected.  When  the  response 
is  in  doubt,  one  must  proceed  to  proof  of  some  sort  before 
the  suggestion  will  be  either  accepted  or  rejected.  It 
should  be  emphasised,  however,  that  in  very  many  cases 
no  formal  proof  is  necessary.  When  the  suggestion  is 
believed,  it  is  at  once  acted  upon  without  any  preliminary 
proof.  The  outcome  of  the  action  is  the  only  test 
required. 

Proof.  —  The  process  that  has  most  concerned  the  logi- 
cian is  proof.  In  its  essentials,  the  process  of  proving 
a  statement  or  conclusion  is  one  of  raising  a  belief  in  the 
mind  of  the  thinker  himself  or  of  a  companion.  Doubt 
is  necessary  to  call  forth  proof.  The  forms  of  proof  are 
ordinarily  divided  into  deductive  and  inductive.  Deduc- 
tive proof  gives  belief  by  referring  the  conclusion  that  is 
in  doubt  to  some  general  principle  or  law  that  has  been 
accepted  in  the  past.  The  new  receives  added  credence 
from  the  old  that  has  itself  been  established.  Induction 


234          ESSENTIALS  OF  PSYCHOLOGY 

draws  the  justification  for  the  conclusion  from  specific 
earlier  experiences  or  from  experiment.  The  most  famil- 
iar form  of  deduction  is  the  syllogism.  In  the  syllogism, 
the  general  principle  by  which  the  conclusion  is  justified 
is  ordinarily  stated  first ;  second,  the  application  of  the 
general  to  the  conclusion  is  made ;  and,  finally,  the  con- 
clusion that  is  to  be  established  is  stated.  It  may  be 
illustrated  in  '  All  metals  conduct  electricity :  tungsten 
is  a  metal,  therefore  tungsten  conducts  electricity.'  It 
should  be  asserted  explicitly  that  the  order  of  thinking  is 
not  the  order  of  the  syllogism,  but  that  the  conclusion 
presents  itself  first,  and  the  rest  of  the  syllogism  is  then  de- 
veloped to  justify  the  conclusion.  One  would  never  make 
a  series  of  statements  of  the  sort,  unless  one  had  started 
to  use  tungsten  to  close  an  electric  circuit  and  someone 
had  questioned  its  value.  The  syllogism  in  practice  is 
developed  to  justify  the  conclusion,  and  develops  after 
the  conclusion  has  been  hit  upon  and  questioned;  the 
conclusion  does  not  grow  out  of  the  major  premise.  In 
actual  everyday  thinking  the  syllogism  seldom  makes  its 
appearance.  The  conclusions  ordinarily  are  rejected  or 
accepted  immediately,  and  no  justification  is  required. 
When  it  does  appear,  it  is  usually  expressed  in  a  much 
abbreviated  form.  In  the  example  given,  one  would  say 
merely,  '  tungsten  is  a  metal,  you  know ; '  and  this  would 
suffice  to  suggest  all  that  is  important  in  the  syllogism. 
One  question  that  might  be  raised  is,  why  does  the  syllo- 
gism or  the  mention  of  the  major  premise  constitute 
proof  ?  The  answer  is  that  it  serves  to  connect  the  con- 
clusion with  the  system  of  concepts  or  general  principles 
that  have  previously  been  accepted.  When  one  sees 


REASONING  235 

that  the  new  suggestion  comes  under  the  old  principles, 
the  belief  that  has  been  developed  for  the  system  of  knowl- 
edge extends  to  the  particular  instance.  The  laws  and 
principles  that  have  been  established  and  accepted  are 
connected  with  the  conclusion  that  is  in  doubt,  and 
doubt  disappears.  Each  doubt  that  is  resolved  increases 
the  belief  in  the  principle,  since  it  assures  its  connection 
with  a  new  fact.  It  should  be  added  that  the  process 
of  reference  to  the  system  of  knowledge,  not  merely 
justifies  the  old,  but  also  increases  the  number  of  applica- 
tions of  the  old.  It  extends  its  application,  and  when  the 
conclusion  itself  is  confirmed  in  practice,  the  general 
principle  receives  new  warrant. 

The  second  form  of  proof,  induction,  is  given  by  a 
reference  of  the  suggestion  to  the  particular  earlier  expe- 
riences. When  questioned  about  tungsten,  one  would  not 
reply  that  it  is  a  metal,  but  would  point  to  an  electric 
lamp,  or  recall  some  other  instance  in  which  it  is  known 
that  tungsten  wire  has  been  used  in  electrical  work.  Or 
one  might  take  the  still  more  empirical  course  of  actually 
testing  to  see  whether  it  does  conduct,  and  whether  the 
resistance  is  low  enough  to  make  it  useful  in  the  partic- 
ular connection.  It  is  probable  that  the  proof  from 
induction  is  much  more  closely  related  to  the  proof  by 
deduction,  than  was  assumed  of  old.  The  particular 
instances,  by  which  the  conclusion  is  justified,  must  be 
in  some  degree  typical  or  they  will  be  valueless.  If 
the  tungsten  used  before  was  mixed  with  some  other 
metal,  it  might  very  well  be  that  the  results  that  held 
of  that  sample  would  not  hold  here.  Unless  again  it  is 
assumed  that  laws  hold  universally,  no  conclusion  can 


236  ESSENTIALS   OF   PSYCHOLOGY 

be  drawn  from  any  number  of  particular  cases.  Each 
new  case  would  needs  be  studied  for  itself,  and  the  results 
of  one  experience  could  not  be  applied  to  a  later  case. 
Again,  as  has  been  seen,  older  developed  concepts  are 
involved  in  any  perception,  so  that  in  each  of  the  particu- 
lar observations  there  must  have  been  general  principles 
involved,  similar  in  kind  to  the  general  principles  that 
warrant  the  conclusion  in  the  syllogism.  On  the  other 
hand,  there  is  always  more  or  less  implicit  reference  to 
particular  experiences  in  the  general  principles  that 
justify  the  conclusion  in  the  syllogism.  The  difference 
between  the  two  sorts  of  proof  is  one  of  emphasis 
only;  the  same  fundamental  principles  are  involved 
in  each.  In  any  case  proof  is  found  in  a  reference  to 
experience,  whether  the  experience  be  that  formulated 
in  concepts  or  general  laws,  or  be  of  raw  particular 
experiences. 

In  brief  outline,  the  process  of  reasoning  is  one  of 
problem-solving,  together  with  justifying  the  solution 
when  it  is  obtained.  The  occasion  for  the  reasoning  is 
always  a  thwarted  purpose.  The  first  step  in  the  solu- 
tion is  to  understand  the  nature  of  the  check,  and  this  is 
accomplished  by  referring  the  present  difficulty  to  some 
old  principle,  to  some  old  concept.  The  second  step  is 
to  obtain  a  solution.  This  is  provided  by  the  laws  of 
association.  Finally,  this  solution  must  be  justified 
when  questioned.  The  justification  is,  ordinarily, 
through  reference  of  the  suggested  solution  to  the  system 
of  earlier  knowledge,  to  the  system  of  concepts.  The 
whole  process  of  inference  is  thus  a  series  of  interactions 
between  the  new  and  the  old  and  ordered  experiences. 


REASONING  237 

The  old  is  constantly  giving  order  and  warrant  to  the 
new,  while  the  old  experiences  are  on  their  side  constantly 
being  extended  and  corrected  by  the  new. 

EXERCISES 

1.  How  may    reasoning,    memory,  and  imagination  be  distin- 
guished ?     Habit  and  reasoning  ? 

2.  How  does  your  abstract  idea  of  a  triangle  differ  from  your 
memory  of  a  particular  triangle  ?     How  do  you  picture  to  yourself 
'machine'  as  a  general  term?     Describe  the  mental  content  fully. 

3.  Can  you  trace  in  your  own  experience,  or  in  the  experience  of 
some  child  you  know,  the  growth  and  extension  of  meaning  that  a 
concept  like  force  has  undergone  ? 

4.  What  do  you  mean  when  you  say  that  you  understand  a  me- 
chanical toy  ?    What  does  seeing  your  way  out  of  an  involved  situa- 
tion imply  ?   How  is  the  process  related  to  judgment  as  it  is  denned 
in  the  text  ? 

5.  Try  to  work  out  an  original  device  of  a  simple  sort ;  e.g.  find  a 
substitute  for  a  stairway  in  your  dwelling.     Record  each  step  in 
the  mental  operation.    Can  you  state  the  process  in  a  single  word  ? 

6.  How  do  you  know  when  the  solution  of  a  problem  is  correct  ? 
How  can  you  demonstrate  its  correctness  to  another  ? 

REFERENCES 

PILLSBURY  :  The  Psychology  of  Reasoning. 

ANGELL  :  Psychology,  chs.  x,  xi,  xii. 

DEWEY:  How  We  Think. 

TITCHENER  :  Text-book  of  Psychology,  pp.  505-507. 


CHAPTER  X 
INSTINCT 

ONE  might  conceivably  treat  man  as  an  altogether  pas- 
sive, intellectual  creature  whose  mental  life  is  restricted 
to  calm  contemplation,  and  whose  contemplation  can  be 
explained  in  terms  of  sensations  and  memories,  and  com- 
binations and  selections  from  sensations  and  memories. 
This  is  far  from  being  the  whole  story.  Man  is  constantly 
acting,  not  only  in  the  light  of  his  own  experience  and 
learning,  but  also  in  terms  of  various  innate  tendencies. 
To  complete  our  description  we  must  add  a  discussion  of 
the  active  and  feeling  side  of  consciousness.  Funda- 
mental to  an  understanding  of  either  action  or  feeling  is 
a  consideration  of  the  different  innate  tendencies  of  the 
individual.  These  are  his  instincts.  They  have  a  pro- 
found influence  on  the  development  of  both  feelings  and 
actions.  All  through  life  they  serve  as  a  background 
for  the  acquired  capacities.  They  also  colour  feeling  and 
determine  action  whenever  experience  fails.  They  often 
conflict  with  the  acquired  and  explicit  knowledge  where 
that  knowledge  has  been  fully  developed. 

Signs  of  Instinct.  —  Instincts  may  be  detected  in  two 
ways.  First,  the  organism  at  birth  exhibits  certain 
responses  that  cannot  have  been  learned.  These 
responses  show  a  very  marked  similarity  in  all  infants. 
The  babe  expresses  his  disapproval  of  the  first  discomfort 
238 


INSTINCT  239 

to  which  he  is  subjected  by  a  violent  outcry.  He  responds 
to  the  first  opportunity  for  nourishment  with  the  appro- 
priate sucking  movements.  All  of  the  immediate 
necessities  of  life  are  provided  for  by  instinctive  responses. 
Second,  in  the  adult  life  there  are  many  responses  and 
feelings  that  cannot  be  explained  by  experience,  that  are 
in  fact  out  of  harmony  with  experience.  These  arise 
spontaneously  and  take  approximately  the  same  form  in 
all  individuals,  although  they  need  not  have  been  present 
at  birth.  Under  this  head  come  the  tendencies  to  self- 
assertion,  the  bashfulness  of  the  adolescent  youth,  many 
fears,  together  with  a  host  of  movements  that  have  not 
been  learned  in  advance  of  their  execution.  Instincts, 
then,  may  be  described  in  one  of  two  ways.  They  are 
movements  that  are  made  at  birth  or  are  movements  that 
show  themselves  relatively  late  in  life,  but  without  any 
preliminary  learning  or  practice.  The  term  is  used  more 
often  in  referring  to  movements,  but  feelings,  too,  often 
appear  that  can  find  no  explanation  in  the  earlier  exper- 
ience. The  disagreeableness  of  bitter  and  the  pleasant- 
ness of  sweet  can  no  more  be  understood  from  the  expe- 
rience of  the  individual  than  the  blushing  of  the  maiden 
or  the  cry  of  the  child.  Fear,  too,  is  at  once  a  movement 
or  a  series  of  movements,  and  a  conscious  state.  Under 
instincts  we  shall  consider  explicitly  or  implicitly  both 
actions  and  feelings. 

The  Physiology  of  Instinctive  Acts.  —  We  may  under- 
stand the  fundamental  nature  of  instincts  best  if  we  con- 
sider what  must  be  the  characteristic  that  is  inherited. 
It  is  now  generally  believed  that  ideas  are  not  inherited. 
There  is  no  evidence  that  a  child  ever  recalls  anything 


240  ESSENTIALS   OF   PSYCHOLOGY 

because  his  father  or  grandfather  saw  it.  One  does  not 
recognise  the  experiences  of  his  parents  or  ancestors 
when  they  are  presented  to  him,  but  the  infant  does  make 
the  same  sort  of  movements  as  did  his  father  and  ances- 
tors before  him.  If  we  turn  back  to  our  discussion 
of  nervous  physiology,  it  is  evident  that  these  movements 
must  have  a  basis  in  the  nervous  system  at  birth.  The 
part  of  the  nervous  system  to  which  we  must  look  for 
an  explanation  is  the  synapse,  the  point  of  connection 
between  nerve-cells.  We  saw  reason  to  believe  that, 
when  a  habit  is  formed,  there  is  some  lessening  of  the 
resistance  that  the  synapse  offers  to  the  transmission  of 
the  nervous  excitation.  In  habit,  the  lessened  resistance 
is  due  to  frequent  early  connection.  Since  instincts 
present  themselves  at  birth,  the  openness  of  the  synapses 
must  be  inherited.  In  brief,  instincts  must  be  something 
physical.  This  physical  characteristic  is  to  be  found  in 
open  connections  between  sensory  and  motor  neurones. 
When  the  stimulus  presents  itself,  the  movement  that 
constitutes  the  instinct  is  at  once  evoked.  How  feelings 
are  transmitted  is  an  unsettled  question,  but  it  is  probable 
that  part  of  the  instinctive  feeling  is  due  to  instinctive 
motor  responses.  Whether  there  are  other  predisposi- 
tions to  response  involved  in  the  dislike  of  bitter,  for 
example,  is  as  yet  unknown. 

Instincts  are  immediately  explained  by  the  inheritance 
of  predispositions  to  response,  the  inheritance  of  open 
connections  between  sensory  and  motor  neurones.  The 
next  problem  that  suggests  itself  is  how  these  connections 
originated.  This  problem,  like  the  problem  of  inheritance 
above,  is  entirely  a  biological  one.  Two  explanations 


INSTINCT  241 

have  been  given  of  the  origin  of  instincts.  The  simpler 
is  that  instincts  are  merely  inherited  habits.  On  this 
theory  some  ancestor  learned  a  movement,  and  the 
movement  was  transmitted  to  his  descendants  and 
became  a  racial  possession.  Were  the  biologist  willing 
to  accept  this  theory,  the  explanation  of  the  origin  of 
instincts  would  be  very  simple.  Unfortunately  the  evi- 
dence that  a  change  wrought  in  one  individual  is  trans- 
mitted to  his  offspring  is  not  accepted  by  the  great 
majority  of  biologists.  Weissmann  has  demonstrated 
to  the  satisfaction  of  many  of  his  colleagues  that  the  struc- 
tures of  the  body  are  set  off  from  the  tissues  that  are  to 
continue  the  race  so  completely  that  the  changes  in  the 
body  have  no  influence  upon  the  inheritance  of  the  off- 
spring. The  cells  from  which  the  progeny  develop  have 
in  potentiality  at  the  birth  of  the  individual  all  the  char- 
acteristics that  they  are  to  develop,  and  they  are  influ- 
enced only  by  the  factors  that  weaken  or  destroy  the 
body  as  a  whole.  Whatever  be  the  outcome  of  the  bio- 
logical controversy,  it  is  necessary  for  the  psychologist 
to  construct  a  theory  of  instinct  on  the  assumption  of 
the  accepted  biological  theory. 

On  this  theory  of  Weissmann,  instincts  come  not 
through  a  change  in  the  habits  of  the  individual,  but 
through  some  chance  change  in  the  characteristics  of 
the  germ  plasm.  It  is  a  fact  that,  while  the  character- 
istics of  the  parent  are  transmitted,  they  are  not  trans- 
mitted accurately,  there  is  always  variation  in  the  char- 
acters. If  one  will  plant  a  thousand  seeds  from  the  same 
plant,  it  will  be  found  that  the  young  plants  show  a  wide 
range  of  variation  from  the  parent  plant  and  from  each 


242  ESSENTIALS   OF   PSYCHOLOGY 

other.  The  theory  of  the  development  of  instincts  as- 
sumes this  same  tendency  to  variation  in  the  nervous 
system  and  in  the  instincts  that  correspond  to  the  nervous 
connections.  If  this  known  fact  of  variation  be  accepted, 
all  that  is  necessary  for  the  development  of  an  instinct 
is  that  some  selection  be  made  from  the  variations.  This 
selecting  agent  has  been  found  by  all  the  evolutionary 
theories  in  the  environment.  When  a  variation  in  re- 
sponse makes  its  appearance  that  is  better  suited  to  the 
environment  than  the  older  responses,  the  animal  that 
shows  the  variation  will  be  better  suited  to  survive  than 
the  others  that  have  only  the  old  response.  If  this  varia- 
tion is  inherited,  as  it  tends  to  be,  the  offspring  of  this  ani- 
mal will  survive  in  greater  numbers  and  in  time  will 
outnumber  those  with  less  adequate  responses.  In  brief, 
variations  in  responses  are  constantly  appearing  as  the 
result  of  changes  in  the  structure  of  the  germ  plasm. 
The  animal  that  has  the  more  beneficial  responses  will 
live  or  its  offspring  will  survive  in  greater  numbers,  while 
any  animal  that  develops  variations  that  are  not  suited 
to  the  environment  will  be  destroyed,  or  the  offspring 
will  be  less  likely  to  survive.  As  a  result  of  this  variation 
in  structure  and  response  from  time  to  time,  with  selec- 
tion of  the  animals  that  show  suitable  variations,  instincts 
become  constantly  more  suited  to  the  conditions  of  life, 
and  also  become  more  and  more  complicated.  Variation 
and  selection  can  account  for  any  instinct,  granted  only  a 
sufficiently  long  time  for  the  variation  to  develop. 

Suppose,  for  example,  that  there  is  a  large  number  of 
rudimentary  organisms  with  all  possible  combinations 
of  two  responses.  Assume,  too,  that  certain  organisms 


INSTINCT  243 

in  the  mass  seek  food  and  flee  dangers,  that  another 
group  flee  from  food  and  seek  the  dangerous  stimulus, 
a  third  group  flee  both  from  food  and  the  dangerous  stim- 
ulus, while  the  fourth  seek  both.  Of  the  entire  group 
only  the  first  class  will  long  survive,  the  others  will  either 
starve  to  death  or  be  eliminated  by  approach  to  danger- 
ous stimuli  or  organisms.  Each  variation  of  the  primary 
responses  in  the  progeny  will  lead  to  similar  elimination, 
or,  as  the  responses  become  more  numerous  and  more 
adequate,  a  greater  proportion  of  the  generation  will 
survive.  In  time,  we  would  have  a  set  of  instincts  that 
would  serve  to  protect  the  organisms  from  the  more 
evident  and  usual  dangers.  The  whole  process  of  devel- 
opment is  thus  due  to  the  development  of  the  structures 
and  the  responses  that  depend  upon  them.  But  it  does 
not  follow  that  instincts  are  necessarily  simple.  Many 
of  the  instincts  even  of  comparatively  low  animals  are 
extremely  complex.  The  egg-laying  instinct  of  the 
Yucca  moth,  cited  by  Lloyd  Morgan,  is  a  case  in  point. 
The  eggs  of  the  moth  are  always  laid  in  the  seed  pod  of 
the  Yucca  plant,  and  after  they  are  deposited,  pollen  is 
gathered  and  placed  with  them.  It  is  a  movement  that 
could  never  have  been  learned  and  the  moth  can  have 
no  idea  of  its  purpose,  for  the  moth  dies  at  once  after  the 
process  is  completed.  The  continuance  of  the  species 
of  both  the  moth  and  the  plant  depends  altogether  upon 
the  accurate  performance  of  the  act.  The  larvae  need 
the  pollen  for  food  when  they  hatch;  the  seeds  of  the 
plant  would  not  be  fertilised  without  the  aid  of  the  insect. 
In  such  a  case  the  instinct  has  all  the  outward  signs  of 
intelligence,  but  must  have  developed  without  the  aid 
of  intelligence. 


244  ESSENTIALS    OF    PSYCHOLOGY 

While  instincts  are  most  striking  in  animals  and,  in 
the  lower  forms,  are  more  easily  distinguished  in  animals, 
they  are  very  numerous  and  important  in  man.  Pro- 
fessor James  asserts  that  man  has  more  instincts  than 
any  other  animal.  A  complete  list  of  instincts  would 
require  too  much  space,  but  it  may  prove  profitable 
to  enumerate  the  more  important  classes  with  some  of 
the  more  striking  instances  under  each  head.  Instincts 
may  be  conveniently  classified  as  individual,  racial,  and 
social.  Individual  instincts  make  for  the  welfare  of  the 
agent,  racial  for  the  continuance  of  the  species,  and  social 
for  the  preservation  of  the  group  or  society.  It  is  not 
always  possible  to  draw  a  sharp  line  between  classes, 
particularly  the  minor  classes,  but  the  broader  lines  of 
distinction  are  clearly  marked. 

Among  the  individual  instincts,  we  may  distinguish 
those  that  care  for  the  essential  movements  of  the  child. 
Here  come  in  order  the  vocal  protests  against  discomfort, 
the  early  and  later  movements  of  taking  nourishment, 
the  movements  of  self-protection,  the  early  locomotor 
movements.  Under  this  head  come  all  the  simple  move- 
ments that  the  child  is  called  upon  to  make  to  meet  the 
demands  of  the  environment.  Many  of  them  are  not 
pure  instincts  or  do  not  long  remain  pure.  An  instinct 
may  lead  to  an  awkward  or  vague  movement,  but  when, 
as  is  usual,  the  movement  is  improved  in  performance 
by  some  chance  variation  in  its  character,  that  de- 
sirable variation  is  likely  to  take  the  place  of  the 
original  movement.  Probably  in  most  of  the  later 
movements,  habit  and  instinct  are  inextricably  confused. 
Whether  learning  to  walk,  for  example,  is  altogether  an 


INSTINCT  245 

instinct  or  not  is  still  an  open  question.  Most  likely  it 
has  an  instinctive  basis,  as  is  shown  by  the  alternate 
movement  of  the  feet  of  an  infant  when  they  are  lightly 
stimulated,  but  a  very  large  part  of  the  development  is 
due  to  habit  formation.  Instinct  and  habit  cooperate 
in  this  as  in  many  of  the  other  simpler  acts. 

Another  striking  group  of  the  individualistic  instincts 
may  be  seen  in  the  fears.  Every  child  at  an  early  age 
and  many  adults  evidence  fears  that  could  not  have  been 
derived  through  experience  and  many  that  are  hi  direct 
opposition  to  knowledge.  The  infant  shows  a  constant 
succession  of  fears  that  appear,  last  for  a  few  days  or 
months,  and  then  disappear,  to  be  replaced  by  others. 
Fear  of  moving  things,  fear  of  living  things  or  of  soft 
things,  fear  of  the  dark,  fear  of  men  alone  or  of  women 
alone,  of  children  but  not  of  adults,  run  their  course  one 
after  another  in  the  first  few  years  of  the  life  of  the  child. 
They  seem  to  appear  without  reason  and  to  vanish  equally 
without  reason.  If  occasion  for  the  fear  develops  in  con- 
nection with  its  instinctive  presence,  it  may  persist  for 
a  long  time ;  if  opportunity  be  given  to  learn  that  the 
fear  is  groundless,  or  if  no  notice  be  taken  of  it,  it  will 
ordinarily  vanish  as  quickly  and  as  unexpectedly  as  it 
came.  Apparently  the  fears  are  the  concomitants  of 
certain  stages  in  the  ripening  of  the  nervous  system. 
When  the  right  stage  appears,  the  instinct  shows  itself ; 
when  that  period  of  organic  transition  passes,  the  instinct 
goes.  Certain  instinctive  fears  persist  into  adult  life. 
Here  one  has  the  fear  of  high  places,  the  fear  of  reptiles 
and  other  small  animals,  the  fear  of  death  and  of  the 
dead,  fear  of  the  strange  and  unexplained,  including  the 


246  ESSENTIALS  OF  PSYCHOLOGY 

supernatural.  These  fears  are  probably  present  in  some 
degree  in  all  individuals  whose  daily  life  has  not  forced 
them  into  frequent  contact  with  the  source.  One  may 
assert  lack  of  fear,  one  may  even  feel  that  the  fear  is 
absurd  and  unintelligible,  but  when  occasion  arises,  the 
proper  response  makes  its  appearance.  One  may  assert 
boldly,  even  haughtily,  an  entire  disbelief  in  ghosts  and 
the  supernatural,  but  the  boldest  sceptic  cannot  pass 
through  a  cemetery  alone  at  midnight  without  feeling  in 
some  slight  degree  uncomfortable,  unless,  of  course, 
such  promenades  have  been  frequent.  Again  one  cannot 
hold  the  finger  relaxed  against  the  glass  of  a  cage  while 
a  rattlesnake  strikes  at  it,  and  that  in  spite  of  positive 
assurance  that  no  harm  can  come  from  the  act. 

In  the  third  class  of  individualistic  instincts  one  finds 
a  large  group  of  activities  that  make  for  the  advancement 
of  the  self,  but  which  have  a  wider  social  reference.  They 
are  to  the  advantage  of  the  individual  in  reference  to  his 
fellows.  Under  this  head  come  pugnacity  and  the  various 
self-assertive  instincts;  here,  too,  fall  the  instincts  for 
collecting  and  secreting  valuables.  This  is  seen  in  the 
collections  of  the  youth,  as  evidenced  by  the  small  boy's 
pocket.  It  is  also  found  in  the  tendency  of  the  miser  to 
accumulate  without  reference  to  use.  Closely  related 
to  this  is  the  instinct  of  emulation  or  rivalry.  This  is 
probably  a  mild  form  of  the  fighting  instinct,  and  may  be 
regarded  as  the  basis  of  the  collecting  instinct  so  far  as 
that  has  a  social  reference.  Piling  up  a  vast  fortune 
may  be  an  expression  of  the  collecting  mania  on  the  one 
hand,  but  it  also  has  in  it  a  large  measure  of  rivalry. 
To  these  may  be  added  the  hunting  instinct  with  its 


INSTINCT  247 

attendant  cruelty,  then  love  of  cruelty  itself,  which  finds 
its  expression  primarily  in  those  slightly  disturbed  men- 
tally. To  these  James  would  add  curiosity,  which  may 
be  transformed  into  a  desire  for  information  and  made  a 
strong  stimulus  to  education,  constructiveness,  and  even 
cleanliness,  in  the  form  of  an  abhorrence  of  filth.  As 
in  the  first  group,  it  is  difficult  to  decide  how  many  of  the 
tendencies  that  are  grouped  under  these  various  heads 
are  really  instincts,  and  how  much  they  have  developed 
as  habits  or  have  been  transformed  in  part  by  habits 
and  experiences  of  various  sorts.  Probably  something 
of  each  is  instinctive,  but  it  is  always  given  direction  by 
habit  and  various  social  influences. 

The  racial  instincts  are  also  very  numerous  and  are 
more  highly  coloured  by  emotion  than  any  of  the  others. 
In  the  lower  animals  they  are  very  widespread  and  very 
striking  for  their  definiteness  and  adequateness,  in  spite 
of  the  slight  knowledge  of  their  purpose  that  can  attach 
to  them.  The  egg-laying  instincts  have  already  been 
illustrated.  The  nest-building  instincts  are  almost  as 
numerous  and  require  greater  complexity  of  response. 
Race  instincts  in  man  are  equally  important  and  show 
as  little  consciousness  of  their  real  purpose  to  the  individ- 
ual that  expresses  them,  as  do  the  corresponding  instincts 
of  the  lower  animals.  The  innocent  adolescent  youth  is 
as  surprised  at  his  thrills  as  he  gazes  upon  the  beautiful 
object  of  his  first  love  and  may  be  as  ignorant  of  their 
cause  and  purpose  as  is  the  beetle  that  is  laying  its  eggs, 
or  the  robin  that  is  building  its  first  nest.  Even  when 
the  instinct  is  understood,  there  is  little  reference  to  that 
knowledge  at  the  moment,  and  the  emotion  is  uncon- 


248  ESSENTIALS   OF   PSYCHOLOGY 

trolled  and  not  altogether  appreciated  in  its  full  bearing. 
Similar  instincts  without  consciousness  of  purpose  and  in 
advance  of  practice  may  be  seen  in  the  coquetry  of  the 
young  girl.  It  apparently  makes  its  appearance  as 
naturally  and  spontaneously  as  the  unfolding  of  a  leaf, 
although  the  art  may  be  perfect  when  measured  by  the 
most  mature  standards.  To  these  various  love  instincts 
must  be  added  jealousy,  which  may  be  as  spontaneous 
and  unreasoned  as  any  of  the  others.  More  important 
are  the  parental  and  filial  instincts  and  the  brotherly 
and  sisterly  affection.  These  are  important  elements  in 
holding  the  family  together.  They  insure  the  care  of 
the  infant  during  the  helpless  stage,  and  the  protection 
and  care  of  the  parent  during  old  age. 

The  social  instincts  have  even  a  wider  range.  They 
vary  from  fear  of  a  single  individual  actually  present 
to  fear  or  consideration  for  the  mass  of  men  of  the  same 
nation  or  race,  even  including  those  known  only  by 
reputation  and  tradition.  The  most  obvious  expressions 
are  seen  in  the  bashfulness  of  a  child  or  youth  in  the 
presence  of  strangers.  Several  recurrent  stages  of  bash- 
fulness  may  be  distinguished.  Apparently  the  young 
child  ordinarily  goes  through  two  or  three  stages  in  fairly 
close  succession.  It  has  a  period  of  being  distressed  by 
any  stranger,  then  becomes  indifferent  or  pleased  by 
people,  then  another  stage  of  bashfulness.  Usually 
there  is  a  recurrence  or  increased  susceptibility  to  bash- 
fulness  about  the  period  of  adolescence,  and  frequently 
still  another  in  boys  in  the  awkward  age  from  eighteen 
to  twenty-one  or  so.  Stage  fright  and  the  fear  of  man 
in  the  mass  under  unusual  conditions  persist  through  life 


INSTINCT  249 

and  apparently  are  overcome  only  by  much  practice,  and 
then  only  for  the  one  situation  in  which  adaptation  has 
developed.  The  opposite  instinct,  sociability,  is  almost 
as  striking  and  shows  itself  during  the  whole  life  of  the 
individual.  From  a  very  early  age,  the  child  resents 
being  left  alone,  and  the  desire  for  the  companionship  of 
friends  is  always  very  strong.  When  long  deprived  of 
the  society  of  his  kind,  one  develops  an  actual  hunger 
for  social  contact  and  conversation. 

The  wider,  more  pervasive  social  instinct  of  sympathy 
is  equally  manifest.  One  cannot  see  the  suffering  of 
another  without  in  some  measure  suffering  himself. 
When  one  gives  a  coin  to  the  beggar  on  the  street  corner, 
one  does  it  not  so  much  to  relieve  the  beggar's  suffering 
as  one's  own.  If  under  the  influence  of  the  teachings  of 
sociology  one  refuses  to  give,  the  thought  of  the  refusal 
will  give  rise  for  some  time  to  an  unpleasant  emotion. 
The  instinct  asserts  itself  in  spite  of  the  belief  that  the 
man  is  an  impostor  and  may  be  better  off  than  one's 
self.  Much  has  been  made  of  this  instinct  by  certain 
of  the  modern  schools  of  ethics  as  the  source  of  all  altru- 
istic action,  and  no  doubt  it  deserves  a  very  high  place 
among  the  forces  that  make  community  life  possible. 
Closely  related  to  sympathy,  if  not  merely  other  expres- 
sions of  the  same  instinct,  are  the  instincts  that  lead  to 
self-sacrifice  for  the  larger  group.  The  soldier  exhibits 
these  together  with  the  fighting  and  hunting  instincts 
when  he  enlists.  Every  instance  of  self-sacrifice  is  the 
expression  of  one  or  the  other  of  the  social  or  racial 
instincts.  If  one  asks  how  an  instinct  that  leads  to  the 
possible  destruction  of  the  individual  could  have  survived 


250          ESSENTIALS  OF  PSYCHOLOGY 

in  the  struggle  for  existence,  one  must  find  the  answer 
in  the  survival  of  the  group  rather  than  of  the  individual. 
Gregarious  animals  are  on  the  whole  more  likely  to  live 
if  the  stronger  are  ready  to  fight  for  the  preservation  of 
the  weaker.  The  male  deer  that  are  said  to  form  a  circle 
about  the  females  and  the  young  when  attacked  by 
wolves  make  possible  the  continuance  of  the  species,  even 
if  a  large  proportion  of  them  succumb  to  the  attack. 
And  in  the  early  stages  of1  human  development  those 
tribes  would  survive  in  which  each  member  would  be 
willing  to  lay  down  his  life  for  the  welfare  of  the  whole. 
Gregarious  animals  survive  in  the  group,  not  individually. 
Two  other  instincts  have  sometimes  been  ascribed  to 
man,  —  play  and  imitation.  It  is  probable,  however, 
that  these  are  not  true  instincts  or  at  least  are  not  single 
instincts.  If  one  will  watch  the  games  of  the  boys  or 
girls  upon  the  school  playground,  one  will  observe  that 
each  game  is  the  expression  of  an  instinct  or  of  many 
instincts.  Emulation  or  rivalry  enters  as  a  factor  in 
almost  every  contest.  Sociability  and  the  advancement 
of  the  welfare  of  the  band  that  is  arbitrarily  formed  can 
be  traced  in  many  of  the  sports.  One  may  even  see  evi- 
dence of  instinct  in  the  content  of  some  of  the  games. 
Playing  with  dolls  is  undoubtedly  an  early  development 
of  the  parental  instinct.  In  general  the  favourite  games 
of  each  sex  show  evidence  of  instinct.  But  the  games 
in  their  specific  forms  are  also  influenced  even  more  by 
the  environment  and  by  the  activities  of  parents  and 
friends.  The  only  thing  that  can  be  said  to  be  common 
to  all  forms  of  play  is  the  tendency  to  some  sort  of  pur- 
posive activity,  the  inclination  of  the  child  to  be  always 


INSTINCT  251 

in  action.  This  is  not  so  much  an  instinct  in  the  ordinary 
sense  as  a  physiological  law,  that  surplus  energy  will 
find  expression  in  action.  Various  instincts  and  habits 
guide  this  expression.  Play  is  the  expression  of  a  law 
of  the  physical  organism,  and  so  far  as  it  is  instinctive, 
it  is  the  expression  of  a  number  of  instincts,  not  of  a 
single  one. 

Imitation  must  fall  into  the  same  general  class.  If 
we  look  upon  instinct  as  an  inherited  connection  between 
sensory  and  motor  neurones,  it  will  follow  that  an  in- 
stinct can  be  nothing  more  than  a  tendency  to  make  a 
single  response  or  a  group  of  responses  upon  the. presen- 
tation of  a  single  stimulus.  Imitation,  on  the  contrary, 
must  always  involve  a  very  large  number  of  responses  to 
many  stimuli.  Imitation  in  general  can  be  either  the 
result  of  many  instincts  or  of  no  instinct.  As  a  matter 
of  fact,  both  statements  hold.  Some  imitative  acts  are 
instinctive,  others  are  the  result  of  habit  and  learning. 
Even  where  learning  is  involved,  there  is  an  instinctive 
element  in  the  interest  that  one  has  in  the  doings  of  other 
people.  This  general  social  instinct  causes  one  to  observe 
the  movements  and,  where  the  results  are  desirable, 
to  make  an  attempt  to  learn  them.  In  infancy,  the  ob- 
servation of  any  movement  makes  the  same  movement 
interesting  when  it  is  made  by  the  child  himself  in  the 
course  of  chance  responses.  Whatever  the  explanation, 
imitation  in  man  leads  to  more  rapid  learning,  even  where 
it  is  not  an  instinct  proper.  Both  play  and  imitation 
have  an  instinctive  basis,  but  neither  is  an  instinct  in  the 
same  sense  as  are  eating  and  fear. 

Habit  and  Instinct.  —  It  should  be  added  and  empha- 


252          ESSENTIALS  OF  PSYCHOLOGY 

sised  that  instinct  and  habit  can  seldom  be  altogether 
distinguished.  In  man  at  least,  instinct  is  always  rela- 
tively unstable  and  vague.  An  act  that  is  purely  in- 
stinctive at  its  first  performance  soon  is  modified  by 
learning,  and  a  response  better  suited  to  the  conditions 
is  pretty  certain  to  develop  sooner  or  later,  and  then  to 
become  fixed  in  habit.  This  may  be  seen  in  the  nest- 
building  instincts  of  barn  swallows  that  must  at  some 
period  have  built  their  nests  in  natural  objects.  It  can 
be  seen  in  the  control  of  fears  in  man  and  in  most  of  the 
other  instinctive  acts.  In  very  many  instances,  too, 
what  is  instinctive  is  not  the  act  so  much  as  the  attitude 
toward  its  result.  One  dislikes  suffering  and  will  take 
any  known  means  to  get  rid  of  it  or  to  avoid  seeing  it; 
the  feeling,  not  the  act,  is  instinctive.  The  end  of  re- 
moving the  unpleasant  or  of  obtaining  the  pleasant  may 
be  attained  in  a  number  of  different  ways,  and  the  par- 
ticular means  of  attaining  the  end  that  is  used  is  deter- 
mined by  habit  or  by  intelligence.  Instincts  of  this 
latter  sort  are  not  stereotyped,  as  are  the  earlier,  more 
primitive  acts  of  instinctive  origin. 

Not  only  are  instinct  and  habit  difficult  to  distinguish 
in  practice,  but  habit  is  constantly  repressing  and  chang- 
ing the  instinctive  tendencies.  Instincts  that  have  de- 
veloped in  one  environment  are  not  suited  to  another  and, 
as  was  seen  in  the  nesting  instinct  above,  may  be  replaced 
by  habits  that  are  suited  to  the  surroundings.  More 
often  in  man  the  instinct  comes  into  conflict  with  tradi- 
tion or  convention  that  again  has  probably  developed 
because  better  suited  than  the  raw  instinct  to  the  de- 
mands and  advancement  of  the  social  group.  It  is  bad 


INSTINCT  253 

form  to  show  greed,  it  is  not  polite  to  exalt  one's 
self.  The  man  of  good  breeding  restricts  these  impulses 
to  the  limits  set  by  his  fellows.  The  racial  instincts  are 
controlled  by  the  laws  of  marriage  and  divorce,  the  in- 
dividual instincts  are  limited  by  the  customs  and  statu- 
tory enactments.  Both  of  these  checks  probably  take* 
their  force  from  some  of  the  social  instincts.  The  fact 
that  man  seeks  social  approval,  and  fears  or  avoids  social 
blame  is  probably  largely  due  to  his  instincts.  Cer- 
tainly to  command  respect  social  disapprobation  need 
never  have  expressed  itself  in  physical  violence  or  the 
infliction  of  bodily  pain.  The  need  for  group  solidarity 
has  become  embodied  in  an  instinctive  respect  for  the 
opinion  of  our  fellows  that  is  at  the  basis  of  what  we 
called  social  pressure  in  the  discussion  of  attention,  and  is 
the  effective  force  behind  both  statutory  enactment  and 
convention.  The  social  forces  that  curb  and  equalise  the 
individualistic  and  racial  instincts  are  themselves  in- 
stincts or  have  a  basis  in  instinct.  It  is  a  social  instinct 
that  receives  its  content  from  tradition  and  custom. 
One  instinctively  feels  a  respect  for  custom  or  convention, 
although  the  custom  or  convention  has  grown  up  through 
habit  and  tradition. 

If  instinct  is  closely  related  to  habit  and  cannot  always 
be  distinguished  from  it,  it  is  also  closely  related  to  reflex. 
In  fact,  the  definition  that  has  been  given  of  instinct, 
that  it  is  an  act  dependent  upon  an  inherited  nervous 
connection,  will  also  apply  without  change  to  reflex. 
The  infant  draws  back  the  hand  when  burned  because  of 
an  innate  connection  between  the  sensory  neurone  that 
receives  the  stimulus  and  the  group  of  muscles  that  con- 


254          ESSENTIALS  OF  PSYCHOLOGY 

tract  in  response  to  it.  The  two  terms  are  confused  in 
popular  speech.  As  a  matter  of  fact  in  psychological 
usage  there  is  much  uncertainty  about  the  exact  line  that 
separates  them.  In  general  one  speaks  of  a  single  response 
as  a  reflex,  of  a  complicated  series  of  responses  as  an  in- 
stinct. Winking  is  a  reflex,  the  complex  series  of  acts 
involved  in  nest-building  is  an  instinct.  The  swallowing 
movement  aroused  when  food  touches  the  back  of  the 
throat  is  a  reflex,  the  whole  group  of  processes  involved 
in  nursing  is  an  instinct.  Again  reflexes  can  be  easily 
reduced  ordinarily  to  a  series  of  mechanically  determined 
responses  to  a  stimulus  or  series  of  stimuli,  while  the 
stimuli  for  instincts  and  their  relation  to  the  responses 
may  not  be  easily  traced.  One  can  understand  why  one 
starts  if  one  steps  upon  a  tack,  but  it  is  not  so  evident 
why  one  starts  at  a  motion  in  the  grass  that  later  con- 
sideration shows  might  have  been  a  snake.  One  does 
not  know  at  all  what  stimuli  lead  a  bird  to  fly  south  in 
the  fall,  but  one  can  see  a  purpose  in  the  action ;  it  is  an 
instinct,  not  a  reflex.  Finally  there  is  ordinarily  more 
consciousness  attaching  to  the  instinct  than  to  the  reflrx. 
One  does  not  know  why  one  gives  money  to  the  beggar, 
but  one  is  conscious  of  doing  so,  and  would  feel  uncom- 
fortable were  it  not  done,  but  the  eye  winks  several  times 
a  minute  with  no  appreciation  of  the  dryness  that  stim- 
ulates the  movement  or  of  the  movement  itself.  In 
some  reflexes  the  act  and  the  stimulus  are  conscious  after 
the  act,  but  the  act  itself  is  not  preceded  or  guided  by 
consciousness.  In  instinct,  ordinarily,  all  is  conscious 
but  the  reason  for  the  act.  Instinct  and  reflex  are  to  be 
distinguished  in  terms  of  the  simplicity  of  the  reflex  and 


INSTINCT  255 

the  complexity  of  instinct ;  by  the  fact  that  the  reflex  can 
be  understood  from  the  mechanical  activity  of  the  ner- 
vous structures,  while  the  instinct  can  be  referred  to  its 
purpose  alone ;  and  in  the  amount  of  consciousness  that 
attaches  to  the  instinct.  No  one  of  these  three  distinc- 
tions would  hold  accurately  in  every  case,  but  taken  to- 
gether they  give  an  idea  of  the  nature  of  the  two  processes. 
Instincts  as  Connate  and  Delayed.  —  It  should  be 
added  in  connection  with  the  differentiation  of  instinct 
from  reflex  and  from  habit  that  the  distinction  cannot 
be  made  on  the  basis  of  the  time  at  which  the  process  or 
activity  makes  its  appearance.  Reflexes  may  be  dis- 
tinguished from  habits  by  the  time  of  the  appearance. 
Reflexes  are  present  at  birth,  are  connate,  while  habits 
require  experience  for  their  development.  Instincts,  on 
the  other  hand,  may  be  either  connate  or  delayed.  They 
may  be  present  at  birth  or  may  appear  only  when  the 
nervous  system  has  attained  a  certain  stage  of  develop- 
ment. It  must  be  said  that  more  of  them  fall  in  the  latter 
group  than  in  the  former.  One  may  recognise  at  birth  the 
rudiments  of  the  food-taking  instincts,  the  vocal  protests 
at  discomfort,  but  relatively  few  others.  The  great  mass 
of  the  individualistic  instincts  and  all  of  the  racial  and 
social  group  can  be  seen  only  after  the  nervous  system  has 
ripened,  and  as  has  been  seen,  one  instinct  after  another 
will  show  itself  as  the  organism  develops.  The  appear- 
ance of  one  fear  after  another  in  the  infant  is  to  be  ex- 
plained by  the  fact  that  part  after  part  or  function  after 
function  of  the  cortex  is  developing,  and  at  each  stage 
the  corresponding  stimulus  calls  out  the  reaction  of  fear. 
But  while  instincts  may  not  be  connate,  unlike  habits 


256  ESSENTIALS   OF   PSYCHOLOGY 

they  are  assumed  to  be  innate.  The  nervous  system  at 
birth  contains  the  germ  from  which  they  are  developed, 
and  while  they  make  their  appearance  after  some  ex- 
perience has  been  acquired,  it  is  not  because  of  the  ex- 
perience. Classified  with  reference  to  purpose,  instincts 
are  individual,  racial,  and  social ;  classified  with  reference 
to  the  time  of  their  appearance,  instincts  are  connate  and 
delayed. 

In  summary  it  may  be  said  that  instincts  are  move- 
ments, or  feelings  that  may  or  may  not  be  the  result  of 
movements,  that  come  because  of  inherited  connections 
and  dispositions  in  the  nervous  system.  In  function 
they  serve,  on  the  one  hand,  to  keep  the  infant  alive  until 
he  may  be  able  to  learn  for  himself,  on  the  other  they 
serve  to  enforce  general  lines  of  conduct  that  are  essential 
for  the  preservation  of  the  individual,  the  race,  and  the 
social  group.  As  opposed  to  habits  and  rational  activi- 
ties, instincts,  of  the  latter  class  at  least,  are  vague  and 
prescribe  only  the  end  to  be  attained,  not  the  precise 
means.  Even  the  first  group  of  instincts  to  make  its 
appearance  is  soon  modified  by  habit,  or  is  repressed. 
Instincts  cannot  be  set  apart  from  habits  and  other  in- 
telligent movements  in  the  adult ;  all  that  can  be  said  is 
that  these  acts  have  an  instinctive  element  or  an  instinc- 
tive basis,  the  others  are  altogether  acquired.  The  ad- 
vantages of  an  inheritance  of  the  vague  outlines  of  action 
only  with  much  left  to  individual  learning  is  evident,  if 
one  will  but  consider  the  relatively  small  number  of  move- 
ments that  may  be  inherited  and  the  great  number  of 
situations  to  be  met,  not  to  mention  the  great  possibility 
of  change  in  the  environment.  Were  an  organism  to  be 


INSTINCT  257 

rigidly  limited  to  a  few  forms  of  response  to  predeter- 
mined conditions,  it  would  soon  find  a  situation  for  which 
it  was  not  prepared  and  be  eliminated.  Or  if  the  en- 
vironment should  change  in  some  way,  the  organism 
could  not  long  survive.  The  present  relation  that  shows 
few  and  relatively  indefinite  innate  responses  with  much 
capacity  for  learning  at  once  relieves  the  necessity  for 
multitudinous  predetermined  responses  and  assures  the 
preservation  of  the  organism  until  it  has  time  to  learn. 

EXERCISES 

1.  Which  of  the  following  acts  are  instinctive,  which  reflex? 
Sneezing;    jumping  when  lightly  touched  on  the  shoulder;    the 
nursing  of  a  child ;  nest-building ;  drawing  back  from  the  edge  of  a 
precipice. 

2.  Enumerate  five  instincts  that  you  have  exhibited  during  the 
day. 

3.  What  were  the  conscious  accompaniments  of  each  of  the  above 
acts? 

4.  A  dog  has  been  taught  to  beg  for  food.     One  of  her  pups  goes 
through  the  begging  movement  without  having  had  any  opportun- 
ity to  see  its  mother  make  the  movement.     Is  this  an  instinct? 
Could  it  have  been  developed  by  training  the  mother  ? 

5.  Give  an  instance  of  an  instinct  that  has  been  modified  as  a  re- 
sult of  learning,  but  is  still  retained  as  an  instinct  in  the  broad  out- 
lines. 

REFERENCES 

JAMES  :  Principles  of  Psychology,  vol.  ii,  ch.  xxiv. 
LLOYD  MORGAN  :  Habit  and  Instinct. 
Animal  Behaviour,  chs.  iii,  vii. 


CHAPTER  XI 
FEELING 

The  Definitions  of  Feeling.  —  The  term  feeling  is  used 
in  many  different  senses.  It  is  made  to  cover  all  sorts  of 
mental  states,  from  the  sensations  received  from  the  skin 
to  the  vague  intellectual  appreciations  of  truth.  We 
'  feel '  with  our  fingers,  and  we  '  feel '  that  certain  things 
are  true  when  we  are  unable  to  prove  them  by  any  formal 
methods.  Feeling  indicates  at  different  times  and  for 
different  people  all  the  vague  experiences.  The  sensa- 
tions from  the  skin  are  regarded  as  less  definite  and  precise 
than  those  from  sight  and  hearing.  In  the  other  fields 
the  same  use  is  predominant.  The  organic  sensations  are 
popularly  classed  as  feelings.  The  psychological  pro- 
cesses that  have  not  been  definitely  analysed,  like  recog- 
nition and  belief,  are  classed  by  many  authors  as  feelings. 

Obviously  it  is  not  possible  to  discuss  all  of  these  dif- 
ferent states  in  one  chapter  or  in  one  connection.  As 
used,  feeling  stands  for  the  unclassified  in  every  field. 
Wherever  we  have  been  able  to  group  facts  about  certain 
typical  phenomena,  we  find  other  similar  facts  that  seem 
to  belong  in  the  same  group,  but  cannot  be  definitely 
described  or  reduced  to  law.  These  constitute  the  feel- 
ings in  the  broader  sense.  Because  they  have  not  yet 
been  reduced  to  types  or  forms,  they  cannot  be  described 
or  defined.  They  are  the  limiting  terms  of  our  science. 
258 


FEELING  259 

Whenever  they  cease  to  be  indescribable  and  take  on 
definite  form,  they  become  something  else  than  feeling. 
Evidently,  feeling  in  this  broader  sense  is  something  that 
cannot  be  discussed ;  when  it  is  possible  to  discuss  it,  it  is 
no  longer  feeling.  Another  objection  to  treating  feeling 
in  this  sense  is  that  there  would  be,  on  this  definition,  as 
many  different  sorts  of  feeling  as  there  are  different 
classes  of  experience.  The  feeling  of  belief  is  no  more 
like  the  feeling  of  discomfort  from  bodily  illness  than  the 
sensation  of  contraction  is  like  a  syllogism ;  the  feeling  of 
recognition  no  more  like  a  feeling  of  moral  virtue  than  a 
memory  image  is  like  a  voluntary  act.  If  one  were  to 
attempt  a  discussion  of  feelings  of  this  kind,  it  would  be 
necessary  to  treat  each  separately,  and  it  would  be  most 
convenient  to  discuss  them  in  connection  with  the  ex- 
periences of  the  same  group  that  have  been  analysed  and 
reduced  to  laws. 

Feeling  as  Pleasantness  and  Unpleasantness.  —  Pleas- 
antness and  unpleasantness  are  the  only  definite  mental 
states  to  which  the  term  feeling  is  applied.  A  descrip- 
tion of  them  is  as  difficult  as  of  any  simple  process,  but 
there  is  no  doubt  what  is  meant  when  the  word  pleasant- 
ness or  unpleasantness  is  used.  Pleasantness  and  un- 
pleasantness are  general  and  are  found  in  connection  with 
practically  every  other  state  and  in  many  different  con- 
nections. One  may  be  pleased  by  impressions  from  any 
sense,  and  by  memories  of  many  different  qualities. 
They  are  foun'd  as  the  accompaniments  of  different  ac- 
tions, in  fact  are  attached  to  all  sorts  and  conditions  of 
mental  processes.  Pleasantness  and  unpleasantness  are 
really  distinct  mental  qualities  and  deserve  a  special 


260          ESSENTIALS  OP  PSYCHOLOGY 

name,  whatever  it  may  be.  Psychologists  are  agreed  in 
calling  these  two  qualities  feelings,  whatever  other  quali- 
ties they  may  add  to  the  list.  We  can  decide  arbitrarily 
to  regard  pleasantness  and  unpleasantness  as  the  feeling 
qualities  and  omit  the  others,  not  because  they  are 
unimportant  in  themselves,  but  because  they  are  not 
feelings  on  the  same  level.  So  far  as  a  discussion  of 
them  is  possible,  it  is  carried  on  to  better  advantage 
in  connection  with  other  subjects. 

Differences  between  Feeling  and  Sensation.  —  Even 
if  we  grant  that  pleasantness  and  unpleasantness  are 
peculiar  states  of  consciousness,  the  question  is  raised 
whether  they  are  distinct  from  sensations.  Ordinarily 
feelings  arise  through  excitation  by  some  stimulus  and 
are  closely  connected  in  origin  with  sensations.  But  we 
may  have  both  feelings  and  sensations  from  the  same 
stimulus  at  the  same  time  and  can  always  distinguish 
them.  The  two  are  never  confused.  Many  formal 
arguments  have  been  devised  to  show  that  they  are 
really  different  sorts  of  mental  content.  Perhaps  the 
most  striking  is  the  general  dependence  of  the  feeling  upon 
the  individual  and  his  peculiar  experiences.  When  the 
same  stimuli  affect  us,  we  see  approximately  the  same 
things,  but  we  feel  very  differently  at  different  times. 
What  pleases  at  one  time  may  displease  at  another. 
What  one  feels  depends  upon  the  individual  and  his  mood 
at  the  moment,  as  opposed  to  the  nature  of  the  external 
stimulus  which  determines  the  nature  of  sensation. 
Feeling  is  as  much  subjective  as  attention,  while  sensa- 
tion is  dependent  altogether  upon  the  physical  environ- 
ment. It  is  in  this  sense  that  feelings  are  subjective, 


FEELING  26l 

sensations  objective.  Coupled  with  this  subjective 
character  of  feeling  is  the  further  fact  that  an  experience 
when  recalled  does  not  always  have  the  same  feeling  as 
at  first.  What  pleased  at  one  time  as  a  boyish  prank 
may  cause  mortification  in  maturer  years.  In  the  same 
way  an  early  social  blunder  that  occasioned  keen  chagrin 
at  the  time  may  now  excite  nothing  but  mild  amusement. 
The  individual  has  changed  in  the  meantime  and  the 
feelings  change  with  the  individual.  That  feelings 
undergo  change  between  the  actual  experience  and  the 
recall,  has  led  to  the  statement  that  we  cannot  remember 
feelings.  It  is  true  that  we  cannot  recall  the  pleasantness 
in  all  of  its  warmth,  but  we  do  recall  the  sensational 
elements  and  receive  the  same  feeling  as  if  it  were  ex- 
perienced at  present.  We  undoubtedly  remember  that 
we  were  pleased  or  displeased,  or  there  would  be  no  ques- 
tion about  the  change  in  feeling.  This  remembrance  is 
in  words  or  other  conceptual  terms. 

This  subjectivity  or  dependence  upon  the  nature  of 
the  individual  and  his  momentary  mood  is  the  most  strik- 
ing characteristic  of  feeling.  Closely  related  to  it  is  its 
lack  of  anything  that  partakes  of  definiteness  or  of  a 
conceptual  character.  Feelings  seem  to  vanish  when  one 
attempts  to  describe  them  or  even  to  attend  to  them. 
Any  attempt  to  analyse  the  characteristics  of  pleasure 
brings  about  a  diminution  if  not  the  disappearance  of  the 
pleasure.  Even  to  ask  whether  one  is  really  pleased  or 
not  has  much  the  same  effect  in  smaller  degree.  Pleasure 
vanishes  when  examined  carefully.  The  mood  of  analy- 
sis is  not  conducive  to  pleasure  and  in  less  degree  is  not 
conducive  to  displeasure.  These  general  characteristics 


262          ESSENTIALS  OF  PSYCHOLOGY 

of  the  feelings  seem  sufficient  to  mark  them  as  distinct 
mental  qualities.  Pleasantness  and  unpleasantness  must 
be  regarded  as  belonging  in  a  different  class  from  sensa- 
tions. 

The  Quality  of  Feeling.  —  Feeling  is  much  less  rich  in 
qualities  than  sensation.  The  qualities  upon  which  there 
is  general  agreement  are  pleasure  and  displeasure,  or 
pleasantness  and  unpleasantness.  They  are  both  op- 
posed to  indifference.  Indifference  by  some  authors  has 
been  made  a  distinct  class  in  addition  to  pleasure  and 
displeasure.  Indifference,  however,  is  probably  merely 
the  lack  of  feeling  and  is  applied  only  to  the  stimulus 
or  to  sensation.  An  indifferent  stimulus  is  one  that 
does  not  give  rise  to  feeling ;  there  are  no  indifferent 
feelings.  There  are  but  two  qualities  of  feeling,  although 
stimuli  that  arouse  feelings  may  be  opposed  to  in- 
different stimuli  or  sensations.  These  indifferent  stimuli 
are  regarded  as  intermediate  between  the  pleasant  and 
the  unpleasant.  The  intermediate  position  is  more  sug- 
gestive if  we  consider  the  degrees  of  pleasantness  and 
unpleasantness  and  their  relation  to  the  intensity  of  the 
stimulus.  Pleasure  and  its  opposite  vary  in  degrees  in 
both  directions  from  just  appreciable  to  very  intense 
feelings.  Wundt  early  suggested  that  there  was  a  con- 
stant relation  between  the  intensity  of  the  stimulus  and 
the  nature  and  degree  of  the  feeling.  Faint  stimuli  are 
ordinarily  pleasant  and  become  less  and  less  pleasant  as 
they  increase  in  intensity,  becoming  first  indifferent  and 
then  unpleasant.  Slightly  sweet  substances  are  indif- 
ferent or  disagreeable.  As  the  degree  of  sweetness  in- 
creases, the  substance  becomes  pleasant,  while  the  intense 


FEELING  263 

sweet  of  saccharine  is  unpleasant.  While  this  relation 
holds  approximately  for  some  senses,  it  cannot  be  re- 
garded as  a  general  law. 

Feeling  and  Affection.  —  It  has  often  been  asserted 
that  there  must  be  different  feelings  for  each  sense  de- 
partment, and  even  for  each  sense  quality.  This  depends 
upon  the  fact  that  one  does  not  distinguish  between  the 
feeling  proper  and  the  sensations  that  accompany  it. 
The  sensations  in  the  complexes  are  different  and  make 
the  whole  complex  different.  The  feeling  proper  is  not 
discriminated  from  the  sensational  colouring.  The  ele- 
mentary feeling  process  is  often  confused  with  the  com- 
plex, even  in  psychological  writing  and  thinking.  To 
avoid  the  confusion  it  has  become  usual  to  apply  the 
term  '  affection  '  to  the  mere  pleasantness  and  unpleas- 
antness apart  from  the  sensational  components,  and  to 
keep  the  word  '  feeling  '  for  the  complex.  For  example, 
in  a  toothache  we  can  distinguish  the  sensation  pain  from 
the  reaction  against  the  pain.  It  is  this  reaction  that 
we  call  the  unpleasant  '  affection.'  The  disadvantage  of 
using  '  affection  '  to  designate  the  element  is  that  it  has 
such  a  widely  accepted  popular  usage  as  the  name  of  an 
emotion.  However,  we  shall  find  it  convenient  to  use  the 
term  in  default  of  a  better  one.  Accepting  this  usage, 
we  may  assert  that  all  affections  are  of  two  kinds,  pleasant 
and  unpleasant,  and  that  all  differences  in  feelings  are 
due  to  the  different  sensations  that  accompany  them. 
The  difference  between  a  toothache  and  a  headache  lies 
in  the  localisation  of  the  pain  sensations,  and  perhaps  in 
some  of  the  accompanying  organic  sensations. 

Sensation  of  Pain  and  Unpleasantness.  —  Particularly 


264  ESSENTIALS   OF   PSYCHOLOGY 

close  is  the  relation  between  the  affection,  unpleasant, 
and  the  sensation,  pain,  which  is  nearly  always  unpleas- 
ant. The  affection  and  the  sensation  are  combined  so 
often  in  a  single  feeling  that  frequently  they  are  not 
distinguished  at  all.  A  few  years  ago  it  was  usual  to  con- 
fuse the  two  and  speak  of  feelings  of  pain  as  well  as  of 
feelings  of  unpleasantness.  Since  pain  organs  have  been 
recognised,  this  usage  is  not  to  be  favoured  unless  the  term 
pain  is  used  in  two  senses,  —  to  designate  both  the  affec- 
tion and  the  sensation.  Pain  sensations  may  be  pleasant, 
as  in  the  pain  excited  by  the  biting  cold  of  a  clear  day 
when  one  is  in  good  health.  The  displeasure  that  is 
caused  by  a  sudden  pain  is  altogether  distinct  from  the 
pain  itself,  although  they  are  fused  into  a  single  complex. 
The  quality  of  unpleasantness  apart  from  its  setting  is 
the  same  in  each  case.  We  may  conclude  that  there  are 
but  two  qualities  of  affection  and  that  differences  in  feel- 
ings come  from  the  sensational  elements  in  the  complex, 
not  from  the  affective  components. 

Sensory  and  Intellectual  Feelings.  —  Other  suggested 
distinctions  are  between  higher  and  lower,  or  sensory  and 
intellectual  feelings.  In  general  the  two  classes  overlap. 
Intellectual  feelings  on  the  whole  are  supposed  to  be 
higher ;  the  sensory,  lower.  The  difference  between  the 
intellectual  and  the  sensory  is  very  much  the  same  as  that 
between  the  different  sorts  of  sensory  feelings  discussed  in 
the  preceding  paragraph.  In  the  intellectual,  the  cogni- 
tive components  are  largely  memory  processes  and  prod- 
ucts of  imagination.  Mental  accomplishments  of  all 
kinds  give  rise  to  pleasure ;  defeat  or  failure  to  perform  a 
mental  operation  resolved  upon  causes  displeasure.  The 


FEELING  265 

resulting  pleasure  or  displeasure  is  the  same  in  each  in- 
stance ;  the  difference  is  in  the  occasion  alone,  the  non- 
affective  accompaniments  of  the  pleasure.  Between  the 
higher  and  lower  pleasures  the  distinction  is  largely 
ethical  or  social,  rather  than  in  terms  of  the  quality  of  the 
affection.  The  higher  pleasures  are  those  that  are  im- 
portant for  the  welfare  of  society  and  correspond  to  ac- 
tivities that  are  not  deeply  ingrained  by  instinct.  Society 
has  given  an  indorsement  to  the  pleasures  of  the  one 
class  because  of  their  benefit  to  the  social  whole,  while  the 
pleasures  of  sense  are  regarded  as  strong  enough  to  take 
care  of  themselves.  The  pleasure  from  a  good  dinner  is 
apparently  no  different  in  its  quality  from  the  conscious- 
ness of  a  good  deed,  but  the  pleasure  attaching  to  a  good 
dinner  is  sufficiently  vivid  and  the  instinct  to  eat  suffi- 
ciently strong  to  need  no  bolstering  from  society,  while  the 
instinct  to  perform  a  good  deed  is  so  weak  that  social 
approval  is  necessary  to  insure  its  performance.  Society 
therefore  expresses  its  approval  by  classifying  the  one 
pleasure  as  higher,  while  its  disapproval  of  the  other  is 
expressed  by  classifying  it  as  lower.  Both  of  these 
classifications  have  no  reference  to  the  affective  quality, 
and  so  do  not  make  necessary  any  change  in  our  earlier 
statement  that  affections  have  but  two  qualities,  pleasure 
and  displeasure. 

Bodily  Accompaniments  of  Feelings.  —  The  bodily 
accompaniments  of  feelings  have  been  made  much  of 
in  psychological  descriptions  and  discussions.  Many 
bodily  signs  of  pleasure  are  apparent  to  the  casual  ob- 
server. When  one  is  pleased,  the  face  is  flushed  due  to 
the  enlarged  capillaries,  the  eye  is  bright  from  the  dilation 


266          ESSENTIALS  OF  PSYCHOLOGY 

of  the  pupil,  the  carriage  is  erect.  In  displeasure  the 
opposed  responses  are  seen.  Attempts  have  been  made 
to  determine  accurately  the  different  component  physio- 
logical states  that  give  rise  to  the  psychical  condition, 
but  the  results  at  present  are  conflicting.  No  exact  op- 
position can  be  shown  between  pleasure  and  pain  in  the 
accompanying  heart  rate,  in  the  size  of  the  capillaries, 
or  in  the  strength  or  rate  of  breathing.  All  of  these  pro- 
cesses undergo  change  in  any  sort  of  feeling,  but  one  can- 
not connect  the  nature  of  the  change  with  the  quality  of 
feeling.  The  outcome  of  the  experiments  on  this  subject 
is  altogether  negative.  The  belief  of  the  earlier  investi- 
gators that  they  had  discovered  a  definite  relation  between 
the  bodily  responses  and  pleasure  and  displeasure  does  not 
harmonise  with  the  results  of  recent  investigations. 

Theories  of  Feeling.  —  Three  theories  have  value  as 
an  explanation  of  the  nature  and  origin  of  feeling  or  of  the 
affective  component  of  the  feeling.  These  are:  (i)  the 
evolutionary  theory  which  is  oldest  and  probably  funda- 
mental for  the  other  two ;  (2)  the  theory  that  relates  feel- 
ing to  association  and  attention ;  and  (3)  the  theory  of 
smooth-running  and  checked  mental  operations.  Each 
has  its  place  and  must  be  considered  separately.  The 
first  asserts  that  pleasure  is  the  accompaniment  of  stimuli 
that  have  in  the  long  run  proved  beneficial  to  the  race; 
displeasure,  the  accompaniment  of  stimuli  that  on  the 
whole  have  proved  injurious.  We  like  foods,  we  dislike 
substances  that  are  unfit  for  food.  There  are  obviously 
many  exceptions  to  this  rule,  but  they  arise  largely  from 
the  fact  that  man  has  evolved,  not  to  meet  each  specific 
case,  but  to  meet  the  general  conditions.  Thus  sugar 


FEELING  267 

of  lead  might  be  mistaken  for  cane  sugar  and  be  con- 
sidered pleasant,  but  to  avoid  all  sweets  would  do  more 
damage  to  the  race  than  to  eat  all  and  have  the  few  who 
chance  upon  the  poisonous  sweets  die  from  them.  Simi- 
larly medicines  are  proverbially  unpleasant,  but  man  has 
not  evolved  to  take  medicine.  They  are  of  value  only 
in  exceptional  conditions.  On  this  theory,  man's  action 
has  been  adjusted  to  the  environment,  and,  as  a  part  of 
the  process,  there  has  been  developed  a  conscious  fore- 
shadowing of  the  effect  of  certain  substances  upon  him. 
He  finds  this  foreshadowing  in  the  pleasantness  that  in- 
dicates a  stimulus  to  be  beneficial,  or  in  the  unpleasantness 
that  gives  warning  of  injury.  The  feelings  come  in  ad- 
vance of  specific  experience.  They  are  of  value  in  plan- 
ning action.  In  many  instances  the  idea  arouses  pleasure 
before  the  action  is  begun,  or  even  before  the  stimulus  is 
received.  Pictorially,  one  may  regard  the  feelings  as 
organic  memories  of  the  effect  of  stimuli  upon  the  race  as 
a  whole  come  to  light  in  the  individual  as  a  member  of  the 
race.  As  a  matter  of  actual  fact,  all  that  this  can  mean 
literally  is  that  all  individuals  who  felt  anything  other 
than  pleasure  from  stimuli  of  this  sort,  or  other  than  dis- 
pleasure from  stimuli  and  ideas  of  another  sort  have  been 
eliminated.  Evolution  and  elimination  have  found  ex- 
pression in  feelings  that  now  signify  for  all  individuals 
the  general  relations  of  the  stimuli  to  the  benefit  or  injury 
of  the  organism. 

The  Experience  Theory  of  Feeling.  —  The  first  of  the 
psychological  theories  of  feeling  seeks  to  explain  the 
changes  that  feelings  undergo  as  the  individual  grows. 
One  of  the  most  striking  phenomena  in  connection  with 


268  ESSENTIALS   OF   PSYCHOLOGY 

feelings  is  that  they  change  their  character  with  the  ex- 
perience of  the  individual.  An  unfortunate  experience 
with  a  particular  dish  may  make  it  unpleasant  long  after 
the  experience  itself  has  passed  out  of  mind.  Some  pleas- 
ures, too,  are  the  direct  expression  of  association.  A 
national  anthem  arouses  a  pleasure  in  the  patriotic  citizen 
that  is  entirely  incommensurate  with  the  artistic  value  of 
the  music.  Wundt  carries  the  theory  a  step  farther  and 
relates  feeling  to  the  activities  that  are  at  the  basis  of 
attention.  The  accumulated  experiences  largely  deter- 
mine the  character  of  attention.  The  character  of  feel- 
ing depends  upon  the  experiences  of  the  individual.  These 
two  statements  may  be  combined  in  the  theory  that  feel- 
ing is  the  outcome  of  attention.  The  ultimate  quality 
of  the  feeling  as  pleasant  or  unpleasant  must  still  be  ex- 
plained by  the  evolutionary  theory.  There  is  nothing 
involved  in  attending  to  a  pleasant  object  that  is  not  also 
involved  in  attending  to  an  unpleasant  one.  Accumu- 
lated experience  only  serves  to  transfer  pleasure  and 
displeasure,  that  originally  came  from  one  experience, 
to  others  with  which  they  were  not  act  first  connected. 
The  pleasure  of  the  song  comes  from  the  social  instincts 
that  have  their  source  in  the  community  of  spirit  with 
fellow-members  of  the  group.  The  pleasure  now  returns 
when  the  song  is  heard.  All  goes  back  to  the  appreciation 
of  benefit  and  injury,  but  appreciation  is  rendered  more 
certain  and  accurate  by  the  later  experiences.  The 
evolutionary  quality  or  character  is  extended  from  the 
immediately  pleasant  stimuli  to  other  and  related  stimuli 
and  qualities  of  sensation. 
The  Furtherance-Hindrance  Theory.  —  The  third  the- 


FEELING  269 

ory  is  favoured  by  Stout  and  Dewey  in  slightly  different 
forms.  Briefly,  pleasure  is  the  accompaniment  of  any 
smooth-running,  uninterrupted  activity;  displeasure,  of 
thwarting  and  interruption.  If  one's  heart  is  set  upon 
the  accomplishment  of  any  task  and  the  task  is  interrupted 
in  its  performance,  displeasure  is  the  result.  Whatever 
furthers  the  progress  of  the  task  gives  pleasure  What  the 
task  is  matters  not.  It  is  as  truly  pleasant  to  progress 
toward  the  solution  of  a  problem  in  mathematics  when 
that  is  the  aim  of  the  moment  as  it  is  toward  the  acquisi- 
tion of  an  automobile  or  the  worldly  wealth  which  that 
signifies.  There  is  undoubtedly  a  very  close  relation 
between  pleasure  and  progress  toward  a  desired  end. 
The  possibilities  of  pleasure  are  dependent  largely  upon 
desires.  This  theory  applies  immediately,  however,  only 
to  relatively  active  processes  or  operations.  The  ap- 
plication is  extended  by  the  use  of  many  similes.  The 
more  general  one  asserts  that  there  are  many  more  move- 
ments than  one  ordinarily  assumes,  that  movements  are 
called  out  hi  relatively  obscure  muscles  and  organs  that 
one  would  never  suspect  to  play  any  part  in  the  operation. 
Lipps  has  suggested  that  these  movements  are  called  out 
by  sympathy,  even  with  inanimate  objects  that  we  per- 
sonify. A  column  that  seems  to  be  supporting  a  load 
beyond  its  strength  excites  our  sympathy  because  we 
seem  to  put  ourselves  in  its  place.  Many  geometric 
figures  excite  our  compassion  and  so  are  unpleasant, 
others  are  pleasant  from  their  complete  adequacy. 

All  Three  Theories  are  Needed.  —  Each  of  these 
theories  has  its  applications.  The  more  fundamental 
activities  and  reactions  must  find  their  explanation  hi 


270  ESSENTIALS   OF   PSYCHOLOGY 

the  evolutionary  feeling.  Fundamentally,  the  organism 
requires  satisfaction  in  certain  ways,  and  there  is  appar- 
ently a  predisposition  to  respond  to  certain  stimuli  by 
the  feeling  of  pleasure,  to  others  by  displeasure.  •  Under 
this  head  come  the  sense  pleasures.  The  associatory 
theory  will  explain  the  many  transfers  and  changes  in 
feelings  that  we  see  in  the  course  of  our  life,  and  the  at- 
tachment of  feelings  to  many  objects  that  are  themselves 
indifferent  to  our  well-being.  On  the  contrary,  the  oppo- 
sition-furtherance theory  is  best  adapted  to  the  explana- 
tion of  the  active  pleasures,  both  physical  and  mental. 
Most  pleasure  from  games  finds  its  explanation  in  ac- 
complishment;  and  the  pleasure  that  accompanies  suc- 
cess in  any  undertaking  has  the  same  explanation. 
Feelings  cannot  be  explained  by  any  one  theory  as 
there  are  different  sources  of  pleasure  and  displeasure. 
All  three  theories  must  be  combined  if  feelings  are  to 
be  understood  in  their  entirety. 

EXERCISES 

1.  Sometime,  when  much   pleased  at    some   happening,  turn 
around  upon  yourself  and  try  to  analyse  the  state  into  its  elements. 
Can  you  distinguish  the  affective  elements  in  the  total  state  from  the 
sensational  components  ?    Does  the  pleasure  disappear  during  the 
analysis  ? 

2.  Can  you  give  pleasantness  or  unpleasantness  a  definite  bodily 
seat  as  you  examine  any  simple  experience  ? 

3.  Try  to  recall  some  pleasure  of  last  week.     Do  you  reinstate  the 
pleasure  or  remember  that  you  were  pleased  ?    In  your  opinion  is 
the  pleasure  as  intense  as  in  the  original  experience  ?    Do  you  recall 
the  pleasure  in  its  vividness,  or  merely  the  sensations  that  were  con- 
nected with  the  experience  ? 


FEELING  271 

4.  Was  the  pleasure  in  the  above  instance  instinctive,  the  result 
of  training  or  experience,  or  an  expression  of  furthered  or  successful 
activity  ?  Recall  different  pleasures  that  can  be  explained  by  each 
of  the  theories. 

REFERENCES 

ANGELL  :  Psychology,  chs.  xiii,  xiv. 
TITCHENER  :  Text-book  of  Psychology,  pp.  225-264. 
STOUT  :  Manual  of  Psychology,  pp.  210-241. 
MARSHALL  :  Pain,  Pleasure,  and  ^Esthetics. 


CHAPTER  XII 
THE   EMOTIONS 

The  Place  of  Emotion  in  Consciousness.  —  The  emo- 
tions stand  as  mental  states,  intermediate  between  feel- 
ings and  instincts  and  the  higher  intellectual  operations. 
From  one  point  of  view,  they  are  very  intense  and  diffuse 
feelings  aroused  by  complicated  situations.  Pleasure  is 
the  result  of  a  mild  response ;  delight,  of  a  response  of  the 
same  general  character  but  more  intense  and  diffuse. 
Emotions,  too,  are  related  to  movements.  When  sur- 
prised, one  starts;  when  one  thinks  of  some  definite 
action  to  perform,  the  movement  is  executed.  In  this 
respect  emotion  is  different  from  voluntary  action  since 
the  movements  in  an  emotion  have  no  relation  to  the 
outside  world,  but  find  their  goal  within  the  body.  In 
emotion,  action  ends  with  facial  expression  or  diffuse 
organic  responses.  In  action  of  the  voluntary  sort,  the 
end  of  movement  is  some  change  in  the  world  outside. 
Most  striking  is  the  relation  of  emotion  to  instinct.  All 
emotions  have  an  instinctive  basis ;  movements  in  emo- 
tional expression  are  the  outcome  of  instinct.  So  true 
is  this,  that  the  emotion  is  defined  as  the  conscious  side 
of  instinct.  For  instance,  fear  is  instinctive,  but  fear  is 
also  an  emotion.  Instinct  is  the  process  viewed  from  the 
outside,  emotion  is  the  same  process  viewed  from  within. 
Every  emotion  has  its  instinctive  side,  every  instinct  its 
272 


THE    EMOTIONS  273 

emotional  side.  Emotion  is  concerned  primarily  with 
the  responses  that  end  altogether  within  the  body ;  im- 
pulses are  the  instincts  that  lead  to  action  directed  be- 
yond the  body  and  will  be  discussed  in  the  next  chapter. 

Ancient  Theories  of  Emotion.  —  The  ancients  always 
spoke  of  the  emotions  as  having  their  seat  in  the  viscera. 
Courage  was  in  the  heart,  jealousy  in  the  liver,  and  the 
other  emotions  each  had  its  seat  in  the  abdominal  region. 
If  one  studies  the  sensations  in  an  emotion,  or  recalls  the 
experience  in  some  old  emotion,  he  will  see  that  the  only 
definite  elements  that  can  be  recognised  are  sensations 
from  the  different  parts  of  the  body,  very  largely  from 
the  viscera.  In  sorrow  there  is  pressure  about  the  heart, 
in  joy  a  feeling  of  lightness  in  the  chest.  The  lump  in  the 
throat,  the  dryness  of  the  membranes  of  the  throat,  all 
contribute  some  part  to  the  total  emotion.  What  can  be 
described  or  remembered  of  the  emotions  are  the  organic 
sensations  that  accompany  them.  These  have  a  definite 
bodily  seat  in  the  chest  and  abdomen,  and  seem  to  be 
more  or  less  closely  related  to  some  of  the  visceral  organs. 
The  fact  that  the  ancients  ascribed  the  emotions  to  these 
organs  may  be  readily  understood  and  explained. 

James-Lange  Theory.  —  The  recent  discussion  follows 
the  same  general  tendency.  The  prevailing  modern 
theory  was  developed  independently  by  James  and 
Lange.  This  theory  makes  emotion  the  subjective  ac- 
companiment and  the  natural  outcome  of  instinct. 
When  a  stimulus  affects  one,  it  calls  out  numerous  re- 
sponses because  of  the  inherited  paths  of  discharge.  These 
are  the  occasion  both  for  the  bodily  attitudes  as  they  are 
presented  to  the  outside  observer,  and  of  the  conscious- 


274  ESSENTIALS   OF   PSYCHOLOGY 

ness  of  the  emotions  as  it  is  revealed  to  the  man  himself. 
Professor  James  insists  that  ordinarily  there  is  no  aware- 
ness of  the  action  or  foresight  as  to  what  it  is  to  be,  until 
the  action  has  been  completed.  For  instance,  he  asserts 
that  as  a  small  boy  he  was  playing  with  blood  without 
knowing  what  it  was.  Suddenly  he  fainted.  Nothing 
in  the  experience  suggested  the  act  or  gave  any  indication 
that  he  was  about  to  faint.  The  consciousness  of  the 
emotion  always  attaches  to  the  act  after  it  has  been  com- 
pleted. "  One  sees  a  bear  and  runs  away.  One  is 
afraid  because  one  runs  away;  one  does  not  run  away 
because  one  is  afraid."  The  act  comes  instinctively, 
almost  reflexly,  as  part  of  the  stimulus ;  no  thought 
intervenes,  no  elaborate  working  over  of  the  material  is 
possible  before  the  action  that  constitutes  the  expression 
and  very  largely  colours  the  emotion. 

Emotion  as  Instinctive  Response.  —  The  theory  of 
emotion  in  terms  of  the  instinctive  response  is  very  gen- 
erally accepted.  There  can  be  no  doubt  that  most  of  the 
vividness  and  life  of  the  emotion  depends  upon  the  bodily 
expression.  One  would  hardly  say  that  one  was  really 
afraid  unless  the  general  quaking  and  motor  insufficiency 
was  felt  together  with  the  sinking  feelings  about  the 
heart.  One  would  not  be  really  angry  unless  one  was 
going  hot  and  cold  and  had  lost  control  of  the  muscles  to 
some  degree.  A  man  who  could  face  a  crisis  and  know 
it  to  be  a  crisis  with  none  of  these  organic  responses 
would  not  really  feel  an  emotion,  no  matter  how  complete 
intellectual  appreciation  he  had  of  the  seriousness  of  the 
situation.  The  emotions  take  their  colour  from  the  bodily 
reverberation,  from  the  sensations  that  arise  from  con- 


THE    EMOTIONS 


275 


tracting  muscles.  These  contractions  are  aroused  by 
the  instinctive  connections  between  the  stimulus  and  the 
muscles.  Up  to  this  point  the  character  of  the  emotions 
is  determined  instinctively.  That  the  emotions  would 
not  have  the  qualities  they  do  have  without  these  in- 
stinctive responses  is  demonstrated  by  the  observations 
of  the  pathologists,  that  when  an  individual  has  wide- 
spread anaesthesia  of  the  body  muscles,  no  emotions  are 
felt  or  at  best  the  emotions  are  not  of  the  same  character 
as  in  the  normal  individual.  The  deep-seated  motor 
response  is  an  integral  part  of  the  emotion ;  the  emotion 
disappears  or  takes  on  an  entirely  different  character 
when  the  response  is  lacking. 

Sometimes  the  objection  is  raised  that  one  does  not 
feel  the  emotion  when  it  is  merely  feigned,  although  this 
may  include  making  most  of  the  movements  involved  in 
the  ordinary  emotional  expressions.  This  suggestion 
led  James  to  ask  actors  whether  they  felt  the  emotions 
that  were  depicted  by  the  characters  they  were  represent- 
ing. As  might  have  been  expected,  actors  divided  into 
classes.  Some  felt  the  emotions  they  portrayed,  others 
were  left  practically  unmoved.  Moreover,  one  could  not 
say  that  there  was  any  relation  between  the  strength  and 
accuracy  of  the  acting,  and  the  degree  to  which  the  part 
was  felt.  Great  actors  were  left  cold  and  equally  great 
ones  felt  the  emotion.  The  difference  arises  probably 
from  the  fact  that  some  individuals  must  feel  the  part  to 
express  it,  others  are  able  to  mould  the  features  without 
reference  to  the  total  complex  feeling.  It  is  probable, 
too,  that  in  many  cases  an  actor  can  separate  the  more 
superficial  from  the  deeper  responses;  he  can  control  the 


276          ESSENTIALS  OF  PSYCHOLOGY 

muscles  of  the  face  and  the  larger  muscles  of  the  trunk 
without  making  the  associated  contractions  of  the  deeper- 
lying  muscles.  The  amount  of  feeling  depends  upon  the 
number  of  such  deeper-lying  muscles  that  are  contracted. 
Emotions  depend  upon  Intellectual  Appreciation  as 
well  as  upon  Instinct.  —  A  second  objection  that  may 
have  even  more  force  is  that  the  expression  of  the  emo- 
tion does  not  depend  always  upon  the  nature  of  the 
stimulus  alone,  but  also  upon  the  interpretation  that  is 
put  upon  the  stimulus,  or  upon  the  resulting  sensation. 
Frequently,  as  in  the  case  of  Professor  James  and  the 
blood,  the  whole  process  is  apparently  immediate.  The 
effect  of  the  stimulus  upon  the  organism  requires  no  inter- 
mediation of  interpretation.  On  the  other  hand,  in  many 
instances  the  response  comes  only  after  the  situation  has 
been  interpreted,  and  then  is  influenced  by  the  interpre- 
tation as  much  as  by  the  stimulus  or  sensation.  Many 
times,  one  does  not  get  angry  until  one  sees  who  is  playing 
the  trick ;  one  is  not  afraid  until  the  full  list  of  circum- 
stances is  taken  into  consideration.  In  other  words, 
the  motor  response  that  is  characteristic  of  the  emotion 
results  upon  the  interpretation  of  the  stimulus,  not  upon 
the  stimulus  itself.  One  sees  a  snake  and  at  first  may 
feel  only  curiosity.  Later  when  the  entire  set  of  circum- 
stances and  all  the  markings  are  considered,  one  begins 
to  grow  cold,  to  shiver,  to  feel  a  sinking  in  the  abdomen, 
and  all  of  the  other  symptoms  of  fear.  This  does  not 
mean  that  the  bodily  response  is  not  an  essential  part  of 
the  emotion,  nor  that  it  is  not  the  most  essential  part  of 
the  colouring  of  the  emotion,  but  it  does  mean  that  the 
reaction  is  not  determined  alone  by  the  relation  of  the 


THE   EMOTIONS  277 

external  stimulus  or  any  small  part  of  it  to  the  older  in- 
stinctive contractions.  One  must  take  into  considera- 
tion in  the  emotion  the  acquired  knowledge  of  the  in- 
dividual as  well  as  the  racial  instincts.  The  emotional 
response  is  to  the  total  situation  plus  its  intellectual 
interpretation  rather  than  merely  to  the  stimulus.  With 
this  addition,  emotion  may  be  defined  as  the  intellectual 
awareness  of  the  instinctive  response.  It  is  the  con- 
sciousness of  the  instinctive  reaction  of  the  individual 
as  a  whole  upon  the  situation  as  a  whole. 

Distinction  between  Emotion  and  Impulse.  —  One 
further  limitation  of  the  definition  of  emotion  as  the  con- 
sciousness that  accompanies  an  instinctive  response  is 
that  in  the  emotion  the  movement  has  no  end  outside  of 
the  body,  while  in  instinct  proper  the  end  of  the  action 
is  to  be  found  in  the  world  without.  Anger  is  anger  in 
the  strictest  sense  only  when  the  emotion  is  not  vented 
on  the  object.  Fear  is  fear  in  this  sense  only  so  long  as 
the  contractions  are  restricted  to  the  body  of  the  man  in 
fear.  Flight  ordinarily  relieves  the  fear  and  is  classed 
as  an  impulse  rather  than  as  an  emotion.  If  we  bring 
together  the  characteristics  of  the  emotions,  we  find  that 
they  are  distinguished  from  the  feelings  by  the  fact  that 
emotion  is  always  a  complex  response  to  a  very  compli- 
cated situation,  while  the  feeling  is  relatively  simple  and 
aroused  by  a  single  stimulus.  A  pin  prick  is  unpleasant, 
but  if  on  examination  you  find  that  one  whom  you  do  not 
like  is  pricking  you,  you  become  angry.  Emotion  never- 
theless usually  contains  something  of  pleasure  or  dis- 
pleasure. Emotions  are  distinguished  from  instincts  or 
impulses  by  the  lack  of  objective  end  for  the  action,  — 


278          ESSENTIALS  OF  PSYCHOLOGY 

the  movements  are  confined  to  vague  contractions  of  the 
body  muscles.  An  emotion  is  related  to  both  feeling  and 
impulse,  and  at  the  extremes  may  easily  be  distinguished 
from  either,  although  the  exact  line  of  division  is  not 
always  easy  to  draw. 

The  Classification  of  Emotions.  —  The  classification 
of  the  emotions  is  one  of  the  disputed  problems  of  psy- 
chology. The  simplest  division  is  with  reference  to  the 
feeling  qualities.  Emotions  are  either  pleasant,  unpleas- 
ant, or,  like  surprise,  indifferent.  Classification  with  ref- 
erence to  time  is  not  so  certain  and  cuts  across  the  other 
altogether.  Hope  is  opposed  to  joy  or  disappointment, 
as  future  to  present  or  past.  They  are  also  classified 
with  reference  to  the  end  of  the  emotion,  as  objective  or 
subjective.  Joy  and  sorrow  are  subjective,  love  and  hate 
are  objective.  After  full  use  has  been  made  of  the 
affective  character,  the  temporal  relations,  and  the  ref- 
erence as  subjective  or  objective  in  classifying  emotions, 
there  are  still  differences  in  emotions  that  depend  upon 
the  nature  of  the  object  toward  which  the  emotion  is 
directed,  as  liking  for  an  object,  love  for  a  person,  and 
upon  the  different  degrees  of  the  feeling  toward  objects, 
as  joy  and  rapture.  The  outcome  of  all  the  historical 
attempts  at  classification  is  disappointment. 

Theory  of  Emotional  Expression.  —  A  question  of  more 
interest  was  raised  by  Darwin  in  his  'Expression  of  the 
Emotions  in  Animals  and  Man,'  as  to  why  different  in- 
dividuals and  members  of  different  races  express  emo- 
tions as  they  do,  particularly  why  they  all  express  them 
in  approximately  the  same  way.  The  first  principle  was 
an  outgrowth  of  the  fact  that  emotions  have  a  definitely 


THE   EMOTIONS  279 

instinctive  basis.  All  facial  and  bodily  expressions  must 
be  regarded  primarily  as  survivals  of  once  useful  move- 
ments, whose  usefulness  has  disappeared.  In  the  early 
stages,  crying  makes  for  the  preservation  of  the  child, 
because  it  attracts  attention  when  it  is  lost,  or  when  in- 
jured or  otherwise  in  need  of  assistance.  The  response 
persists  after  it  has  ceased  to  be  useful.  Aside  from  ex- 
pressions that  have  been  directly  useful  at  some  time  in 
the  development  of  the  species,  there  are  transfers  of 
expressions  from  the  original  connection  to  others  where 
they  are  not  of  value.  Darwin  recognised  two  principles 
of  transfer.  First,  expressions  that  have  once  been  use- 
ful in  a  given  connection  are  transferred  to  other  similar 
emotions.  The  sneer  of  man  is  the  remnant  of  the  un- 
sheathing of  the  teeth  in  an  animal.  The  man  feels  as 
the  dog  does  in  preparing  for  the  attack.  He  expresses 
himself  in  the  same  way,  although  it  is  no  longer  cus- 
tomary to  fight  with  the  teeth.  The  nod  of  affirmation 
is  a  metaphor  that  has  been  transferred  from  the  motion 
of  the  head  that  the  child  makes  in  taking  food  into  the 
mouth ;  the  shake  of  the  head  in  negation,  a  transfer  from 
the  child's  act  in  moving  the  head  quickly  to  avoid  tak- 
ing unwelcome  food  into  the  mouth.  Darwin's  second 
principle  is  of  rather  less  general  application.  It  runs 
that  opposed  emotions  are  expressed  in  opposite  ways. 
Darwin's  best  instance  is  the  expression  of  delight  or 
friendliness  in  the  cat.  When  the  cat  is  angry,  it  lashes 
its  sides,  crouches  for  the  attack  to  be  made  as  incon- 
spicuous as  possible.  When  pleased,  the  attitude  is  just 
the  reverse,  —  the  back  is  arched,  the  tail  is  held  erect, 
and  everything  is  as  conspicuous  as  possible.  In  addition 


280  ESSENTIALS   OF   PSYCHOLOGY 

Darwin  has  a  group  of  expressions  left  unexplained  which 
he  refers  to  the  mere  nervous  overflow  —  for  instance,  the 
turning  grey  of  the  hair  from  fright  (if  the  fact  be  ac- 
cepted), and  the  standing  on  end  of  the  hair.  Of  these 
principles,  the  second  and  third  seem  less  well  established. 
The  metaphorical  transfer  of  emotional  expression  is 
accepted  in  some  form  by  practically  all  and  has  many 
applications.  The  more  general  principle,  that  expres- 
sion is  the  survival  of  instinctive  responses  that  were 
once  valuable,  is  lundamental  to  all  theories.  The 
expressions  are  slight  remnants  of  movements  once  im- 
portant for  the  survival  of  the  individual  in  the  circum- 
stances which  now  call  out  the  emotion. 

Emotional  Control.  —  Control  of  emotion  or  of  emo- 
tional expression  is  largely  in  terms  of  the  attitude  one 
takes  toward  the  stimulus  or  sensation.  A  caress  from 
one  person  may  please  or  be  a  matter  of  indifference, 
from  another  may  cause  anger ;  what  occasions  anger  in 
one  mood  may  give  pleasure  in  another  mood  or  attitude. 
The  attitude  is  in  large  measure  under  one's  control. 
From  the  nature  of  the  organism  and  its  inheritance, 
certain  objects  or  stimuli  must  call  out  one  response, 
and  one  alone.  But  aside  from  these  most  fundamental 
instincts  and  stimuli  which  fall  into  the  one  class, 
sensations  and  stimuli  are  susceptible  of  different  classi- 
fications, and  when  classified,  arouse  the  emotion  that 
belongs  to  the  class.  Whether  a  remark  falls  into 
the  group  of  jests  or  of  insults  is  largely  often  a  mat- 
ter of  chance,  and  dependent  upon  circumstance.  The 
emotions  may  be  controlled  only  in  so  far  as  it  is  pos- 
sible to  vary  the  classification  of  the  stimulus.  How 


THE   EMOTIONS  281 

it  is  to  be  classified  depends  very  largely  upon  how  it 
is  attended  to. 

Mood.  —  Closely  related  to  emotion  are  mood  and 
temperament.  A  mood  is  an  emotion  of  longer  duration 
and  ordinarily  of  less  strength  or  violence.  A  mood  is 
usually  a  matter  of  hours  or  days  and  is  a  predisposition 
to  an  emotion  of  a  certain  kind  rather  than  an  actual 
emotion.  So  one  finds  one's  self  in  a  cheerful  mood  in 
which  everything  that  is  pleasant  has  a  definite  appeal,  or 
in  a  depressed  or  angry  mood  in  which  anything  whatever 
is  likely  to  arouse  an  emotion  of  anger  or  a  state  of  de- 
pression. One  is  '  set '  for  an  emotion  of  one  kind  or  of 
one  general  class,  and  as  a  consequence  it  is  very  much 
easier  than  usual  to  arouse  an  emotion  of  that  class.  At 
times  there  seems  to  be  an  incipient  emotion  in  advance 
of  any  stimulus.  One  may  feel  mildly  cheerful  during 
a  day  in  advance  of  any  emotion  and  irrespective  of 
particular  stimulus,  but  mood  is  not  necessarily  conscious 
in  advance  of  the  stimulus  that  excites  the  emotion. 
The  mood  may  owe  its  origin  to  some  particular  stimulus 
or  group  of  stimuli,  or  it  may  be  due  to  the  state  of  health. 
A  piece  of  good  fortune  induces  a  pleasant  mood  that  for 
a  long  time  makes  pleasant  emotions  easy;  any  mis- 
fortune tends  to  reduce  the  capacity  for  enjoyment  and 
increases  the  liability  to  disagreeable  emotions  over  a 
period  of  hours  or  days.  On  the  other  hand,  perfect 
health  and  a  bright  day  are  sufficient  to  induce  a  pleasant 
mood,  while  nothing  is  so  conducive  to  low  spirits  and 
unpleasant  moods  as  bad  health. 

Temperament.  —  Temperament  is  a  mood  that  is 
permanent.  Individuals  are  born  apparently  with  ten- 


282  ESSENTIALS   OF   PSYCHOLOGY 

dencies  to  look  on  the  bright  or  dark  side  of  life.  If  it 
is  not  certain  that  the  temperament  is  innate,  at  least  it 
has  become  permanent  in  early  life  and  seldom  changes 
completely  after  maturity.  The  psychology  of  tempera- 
ments leaves  much  to  be  desired  so  far  as  classification  is 
concerned.  With  the  whole  of  the  psychology  of  in- 
dividual differences,  it  has  received  more  recognition 
for  its  importance  than-  labour  toward  its  development. 
One  may  pick  out  quite  easily  from  his  acquaintances 
individuals  who  are  particularly  prone  to  emotions  of 
one  kind  or  another,  but  to  determine  what  the  most 
striking  features  of  the  temperaments  are  and  to  group 
them  in  a  satisfactory  way  is  by  no  means  so  easy. 
Psychology  is  still  accustomed  to  make  use  of  the  classes 
of  the  ancients,  —  phlegmatic  and  sanguine,  melancholic 
and  choleric.  This  classification,  according  to  Wundt, 
considers  only  the  strength  and  quickness  of  the  indi- 
vidual, not  the  permanent  mood  or  susceptibility  to 
emotions.  The  sanguine  individual  combines  quickness 
with  weakness;  the  choleric,  quickness  with  strength; 
the  melancholic  is  slow  and  weak ;  the  phlegmatic,  slow 
and  strong.  While  these  qualities  are  the  only  ones  made 
explicit  by  the  classification,  there  is  implied  in  the  terms 
as  ordinarily  used  a  predisposition  to  different  emotions 
and  tendencies  to  be  easily  pleased  or  displeased.  The 
melancholic  individual  is  undoubtedly  predisposed  to 
grief  or  low  spirits,  as  is  the  sanguine  individual  to  pleas- 
ant emotions.  The  choleric  individual  is  predisposed 
to  anger,  as  the  phlegmatic  to  calm  even  amid  tempta- 
tions to  excitement.  This  classification,  old  as  it  is,  can 
be  regarded  as  no  more  than  a  beginning  in  the  study  of 


THE   EMOTIONS  283 

individual  differences.  Much  more  remains  to  be  done 
and  could  be  done  with  relatively  little  difficulty.  It  is 
sufficient  to  indicate  that  men  are  differently  disposed 
toward  different  emotions,  and  that  some  respond  easily, 
others  with  difficulty.  What  emotion  shall  be  excited 
depends  fully  as  much  upon  the  individual  as  it  does  upon 
the  stimulus. 

EXERCISES 

1.  Give  an  instance  of  an  emotion  and  of  a  feeling.    How  are 
they  different  ? 

2.  Recall  some  strong  emotion.    How  did  it  affect  the  accuracy 
of  your  thinking  ?     The  efficiency  of  your  acts  ? 

3.  Can  you  recall  any  instance  of  true  emotion  without  bodily 
reactions  ? 

4.  How  are  the  motor  responses  in  anger  different  from  those  in 
fear  ?    In  joy  from  those  in  hate  ? 

5.  Do  the  bodily  expressions  precede  or  follow  the  emotion  as  a 
mental  process  ? 

6.  Can  the  emotion  or  its  expression  be  repressed  or  modified  ? 
Does  experience  change  the  original  character  of  the  emotion  or  its 
expression  ?    How  does  it  resemble  instinct  in  these  respects  ? 

7.  Describe  the  facial  expression  in  anger,  in  joy,  in  sorrow. 
Does  the  facial  expression  contribute  anything  to  the  quality  of  the 
emotion  ? 

REFERENCES 

JAMES  :  Principles  of  Psychology,  vol.  ii,  ch.  xzv. 
TITCHENER:  Text-book  of  Psychology,  pp.  471-503. 
ANGELL  :  Psychology,  chs.  xviii,  xix. 
STOUT  :  Manual  of  Psychology,  Bk.  iii,  ch.  iv. 
JASTROW:  The  Qualities  of  Men. 


CHAPTER  XIII 
ACTION  AND   WILL 

THE  most  important  practical  problem  in  psychology 
concerns  the  control  of  action.  Practically  all  thinking 
and  very  much  of  feeling  and  emotion  are  of  value  to  the 
organism  only  as  they  lead  to  action  of  some  sort  or 
other.  The  aim  of  this  chapter  is  to  determine  how  the 
states  that  have  been  considered  up  to  this  point  are 
effective  in  the  control  of  action.  This  statement  im- 
plies that  action  is  very  closely  related  to  thought  and 
feeling.  The  implication  is  true  in  the  widest  sense. 
All  action  grows  out  of  thinking,  so  far  as  it  is  controlled 
at  all ;  and,  on  the  other  hand,  only  in  and  through  the 
sensory  processes  can  one  appreciate  movement,  can  one 
know  of  action.  As  was  asserted  in  connection  with  the 
discussion  of  the  nervous  system,  all  action  is  sensori- 
motor ;  it  begins  in  sensation  and  ends  in  muscular  con- 
tractions. One  may  complete  the  circle  by  the  assertion 
that  when  the  muscles  contract,  they  arouse  processes  in 
the  sensory  ends  in  the  body  of  the  muscle  tissue,  and 
these  sensory  processes,  in  their  turn,  give  the  only  evi- 
dence to  consciousness  of  the  contraction  of  the  muscle. 
One  can  move  a  muscle  only  through  the  excitation  of 
some  sensory  element,  either  through  the  sense-organ  or 
by  memory,  and  one  can  know  of  the  movement  of  that 
284 


ACTION  AND   WILL  285 

muscle  only  through  the  stimulation  of  the  sensory  ends 
in  the  muscle  that  contracts. 

Evidently,  the  various  problems  in  connection  with 
action  are  problems  of  the  control  of  thoughts  and  of 
sensations,  and  of  the  connections  between  thoughts  and 
sensations,  and  actions.  The  classification  of  actions 
must  be  either  in  terms  of  the  mental  processes  that 
induce  or  that  accompany  action,  or  in  terms  of  the 
nature  of  the  connection  between  the  movements  and 
the  ideas.  Each  of  these  criteria  has  been  used  in  the 
generally  accepted  classification.  One  divides  actions 
according  to  the  amount  of  consciousness  that  precedes 
or  accompanies  the  action ;  the  other,  with  reference  to 
the  way  the  connection  between  sensory  and  motor  ele- 
ment is  established.  In  terms  of  consciousness,  actions 
are  classified  as  impulse,  reflex  act,  and  voluntary  act. 
In  the  technical  psychological  vocabulary,  any  movement 
that  grows  out  of  sensation  or  memory  image  is  called  an 
impulse.  In  the  complete  impulse,  sensation  is  followed 
by  movement,  and  that  is  followed  or  accompanied  by 
a  kinaesthetic  sensation  which  informs  the  agent  that  he 
is  moving  or  has  moved.  In  most  of  the  frequently  re- 
peated movements,  the  consciousness  that  precedes  or 
accompanies  the  movement  falls  away.  Reflex  action 
is  frequently  not  appreciated;  both  the  stimulus  that 
calls  it  out  and  the  sensory  processes  that  accompany  it 
may  pass  unnoticed.  One  winks  without  being  aware  of 
it  or  of  its  stimulus.  In  other  instances,  as  when  one 
draws  back  the  hand  on  being  pricked  with  a  pin,  one  is 
conscious  of  the  stimulus  and  of  the  movement,  but  only 
after  the  response  has  been  made.  Reflex  action  is 


286          ESSENTIALS  OF  PSYCHOLOGY 

distinguished  from  impulse  by  the  fact  that  the  conscious 
accompaniments  either  disappear,  are  reduced  in  number, 
or  enter  consciousness  after  the  movement  has  been 
executed.  The  more  complicated  acts  may  all  be  de- 
fined in  terms  of  impulse  and  the  sort  of  consciousness 
that  accompanies  them.  Voluntary  acts  are  marked 
by  the  fact  that  several  impulses  are  possible  and  that, 
in  consequence,  consciousness  is  more  complicated  than 
in  impulse.  Each  idea  that  is  present  has  its  own  natural 
outcome  in  movement,  and  each  of  these  partial  move- 
ments adds  something  to  the  total  consciousness.  In 
automatic  acts,  the  consciousness  that  accompanies  the 
movement  at  first  has  disappeared,  and  the  movement  is 
run  through  without  definite  knowledge.  This  is  true 
of  walking,  talking,  and  of  most  of  the  more  complicated 
actions  that  have  become  habitual.  If  reflex  acts  are 
to  be  defined  as  impulses  that  have  lost  some  or  all  of 
their  conscious  accompaniments,  volitional  acts  may  be 
defined  as  acts  that  are  performed  after  a  conflict  of  im- 
pulses. The  consciousness  is  more  complicated  than  in 
the  impulse,  because  each  impulse  adds  something  to  the 
total  consciousness. 

One  may  define  acts,  however,  not  merely  in  terms  of 
the  accompanying  consciousness,  but  also  with  ref- 
erence to  the  time  at  which  the  connection  between 
thought  and  action  was  established.  On  this  basis 
impulses  may  be  classified  as  inherited  and  acquired. 
The  former  are  due  to  connections  between  sensation  and 
movement  that  are  established  before  the  birth  of  the 
individual.  The  child  is  born  with  the  synapses  between 
certain  sensory  regions  and  certain  motor  regions  already 


ACTION  AND   WILL  287 

open.  Inherited  impulses  may  be  divided  again  into 
reflexes  and  instincts.  As  was  said  earlier,  reflexes  are 
simple  and  can  be  understood  in  terms  of  the  mere 
physiological  connections,  while  instincts  are  more  com- 
plex and  at  present  can  be  explained  only  through  an 
appeal  to  their  purpose.  Acquired  impulses,  on  the 
other  hand,  are  only  potentially  represented  in  the  in- 
dividual at  birth ;  they  are  the  outcome  of  connections 
that  are  made  or  confirmed  by  action  during  the  life 
of  the  individual.  If  we  combine  the  results  of  the 
two  classifications,  we  find  that  inherited  impulses  are 
more  likely  to  be  unaccompanied  by  consciousness  than 
are  acquired,  although  acquired  impulses  with  practice 
rapidly  lose  their  conscious  accompaniments.  It  should 
be  remarked  that  movements  are  always  excited  by 
sensory  stimuli,  whether  these  are  conscious  or  not,  and 
that  there  are  always  many  more  stimuli  involved  hi  the 
control  of  the  movement  than  are  conscious. 

Obviously,  the  first  problem  hi  connection  with  move- 
ment is  to  determine  the  methods  by  which  movements 
may  be  learned.  The  first  experiments  on  learning  that 
proved  fruitful  were  performed  on  animals.  An  animal 
was  confined  in  a  box,  provided  with  a  door  closed  by 
some  simple  device,  and  the  methods  by  which  the  ani- 
mal learned  to  get  out  were  recorded.  The  results  dem- 
onstrated that  learning  was  the  result  of  chance.  The 
cat  would  struggle  vaguely,  trying  all  of  its  acquired  and 
inherited  responses  one  after  the  other.  It  would  bite 
here,  there,  and  everywhere,  would  scratch  at  each  pro- 
jecting part  and  at  each  crevice,  until  finally  some  one 
of  the  movements  happened  to  open  the  door.  When 


288  ESSENTIALS    OF   PSYCHOLOGY 

returned  to  the  box  at  another  time,  it  would  run  through 
the  same  series  of  random  movements,  until  the  suc- 
cessful act  was  repeated.  Gradually  the  time  required 
would  become  shorter  until,  with  frequent  repetition,  the 
movement  would  be  learned,  and  the  sight  of  the  cage 
would  at  once  call  out  the  correct  response  for  opening 
the  door.  Nervously  this  means  that  the  movement, 
that  comes  at  first  by  chance,  is  established  by  repetition. 
The  synapse  that  opened  frequently  on  this  stimulus 
may  be  pictured  as  getting  more  and  more  permeable, 
until,  when  learning  is  complete,  the  sensation  leads  at 
once  to  the  appropriate  motor  discharge. 

The  same  general  law  has  been  shown  to  hold  as  well 
for  human  learning.  One  of  the  best  instances  of  this 
is  to  be  found  in  the  way  a  man  solves  a  mechanical 
puzzle.  He  may  merely  think  it  through  and,  after 
solving  it  in  thought,  test  the  solution  in  practice.  But 
unless  very  familiar  with  other  forms  of  puzzles,  he  more 
likely  will  go  to  work  just  as  the  cat  does  to  get  out  of 
a  box.  If  the  problem  is  to  take  apart  two  construc- 
tions of  wire,  he  will  try  to  put  one  through  each  place 
that  seems  possible,  and  will  keep  trying  until  he  succeeds 
in  the  attempt.  When  he  gets  them  apart,  the  chances 
are  that  he  will  have  no  very  clear  idea  of  how  it  was 
done.  He  will,  at  most,  remember  in  a  vague  way  the 
point  of  least  resistance,  but  ordinarily  he  must  solve  the 
puzzle  more  or  less  accidentally  several  times  before  he 
can  remember  exactly  how  to  do  it  again,  or  be  able  to 
succeed  at  the  first  trial.  Practically  all  unfamiliar  com- 
plicated acts  are  performed  in  this  way.  Random 
movements,  with  stamping  in  of  the  accidental  success 


ACTION   AND    WILL  289 

through  frequent  repetition,  is  the  universal  method  of 
human  as  well  as  of  animal  learning. 

This  law  is  illustrated  still  more  completely  by  the 
child.  At  birth  the  movements  of  the  child  are  all 
pretty  well  tied  together.  When  the  child  moves  one 
hand,  the  other  moves  in  the  same  way  and  about  as  far. 
If  you  watch  the  feet,  you  will  see  that  they  ordinarily 
move  in  harmony  with  the  movements  of  the  hand. 
Any  stimulus  calls  out  many  more  movements  than  are 
needed.  Even  at  the  age  when  a  child  learns  to  write, 
the  different  members  are  still  more  or  less  bound  to- 
gether. The  boy  follows  the  movements  of  his  hand 
by  sympathetic  rolling  of  his  tongue.  The  process  of 
learning  is  one  of  waiting  until  these  diffuse  motor  dis- 
charges bring  a  pleasant  result,  and  then  of  repeating 
the  movement  that  gave  that  result  until  it  is  thoroughly 
connected  with  the  appropriate  stimulus.  After  this, 
progress  in  learning  is  largely  a  matter  of  separating  the 
particular  element  desired  from  the  complex  in  which  it 
first  originated.  Learning  to  speak  is  an  illustration  of 
the  method.  The  child  of  six  months  to  a  year  spends 
much  of  its  comfortable  waking  time  practising  vocal 
exercises.  At  first  the  results  are  altogether  indefinite 
and  uncertain.  All  sorts  of  noises  come  out  of  the  vocal 
organs.  Whenever  one  that  pleases  the  child's  fancy 
makes  its  appearance,  it  is  repeated,  more  or  less  ac- 
curately, until  thoroughly  learned.  Learning  words 
follows  the  same  laws.  When  a  sound  is  hit  upon  that  is 
similar  to  a  word  that  has  been  heard  from  the  parents, 
that  sound  pleases  the  fancy  of  the  child.  It  is  repeated 
and  the  results  of  the  repetition,  in  the  pleasure  of  the 


2QO          ESSENTIALS  OF  PSYCHOLOGY 

parents  and  in  obtaining  the 'satisfaction  of  its  desires, 
serve  to  increase  the  pleasantness  of  the  movement  and 
to  renew  the  struggles.  The  words  that  are  heard  do 
not  serve  as  the  stimulus  for  their  repetition,  but  set  a 
pattern  toward  which  the  child  may  strive,  or  merely 
make  the  word  interesting  when  by  chance  it  is  uttered. 
Each  of  the  other  motor  accomplishments  is  acquired 
by  the  child  in  the  same  way. 

After  a  fair  number  of  movements  have  been  learned, 
the  first  attempts  at  a  new  movement  are  more  nearly 
successful.  If  the  child  has  had  some  experience  with 
a  pencil  in  drawing,  the  first  attempts  at  writing  will  not 
be  so  awkward  as  the  first  attempts  at  drawing.  The 
movements  will  all  resemble  the  result  that  is  desired.  At 
this  stage,  the  movements  that  are  most  like  those  to  be 
learned  will  be  used  first.  Still,  the  method  of  modifying 
the  old  to  obtain  the  new  follows  the  same  laws  as  the 
original  learning.  One  first  makes  some  familiar  move- 
ment that  is  similar,  and  then  tries  to  vary  that  until  the 
end  is  attained,  but  the  modifications  are  struggled  for  in 
the  same  random  way  as  in  original  learning.  Many  trials 
and  numerous  discouraging  failures  are  usually  required 
before  the  desired  modification  presents  itself.  When  it 
comes  once,  it  can  be  called  out  a  second  time  only  after 
numerous  trials.  Each  success  makes  new  successes 
more  likely,  but  perfection  in  any  movement  comes  slowly. 
When  one  begins  to  learn  the  golf  stroke,  one  ordinarily 
has  a  number  of  similar  movements  at  command.  One 
has  swung  an  axe,  or  has  cast  a  fly,  or  practised  hitting 
at  pebbles  with  a  stick.  One  calls  upon  some  one  of  these 
when  the  first  occasion  comes  for  hitting  the  ball.  The 


ACTION   AND   WILL 


29I 


probability  is  that  the  first  attempts  will  be  inaccurate ; 
certainly  they  will  be  feeble.  The  process  of  transforming 
the  familiar  habits  into  adequate  new  ones  is  one  of  con- 
stant trial  and  slow  selection  of  the  successful  variations. 
In  the  more  complicated  and  delicate  movements  of  this 
sort,  one  frequently  does  not  know  what  it  is  that  makes 
the  successful  stroke,  but,  with  practice,  it  is  always  possi- 
ble to  succeed.  The  conscious  antecedents  seem  to  be  very 
little  different  in  the  successful  stroke  from  those  that  are 
present  in  the  unsuccessful,  but  practice  brings  the  suc- 
cessful stroke  more  frequently.  Assuming,  then,  that  an 
individual  has  a  large  number  of  impulses  under  control, 
whether  they  have  been  established  by  earlier  practice  or 
are  instinctive,  we  find  that  new  movements  are  learned 
by  slow  and  painful  modification  of  these  responses. 

The  Acquisition  of  Skill.  —  Closely  related  in  explana- 
tion and  in  practice  to  the  learning  process  is  the  acquisi- 
tion of  skill.  When  one  has  mastered  the  separate  move- 
ments that  are  necessary  for  the  accomplishment  of  some 
important  end,  the  process  of  combining  them  and  con- 
trolling them  in  such  a  way  as  to  give  rapid  and  accurate 
accomplishment  offers  much  that  is  of  interest  psycholog- 
ically, and  is  also  of  much  practical  importance.  Many 
investigations  have  been  made  of  the  methods  of  acquiring 
skill  in  telegraphy,  in  typewriting,  tossing  balls,  and  in 
various  other  games  and  occupations.  The  rough  results 
show  striking  agreement  among  the  different  investigators, 
and  for  different  sorts  of  learning.  Learning  has  a  char- 
acteristic course.  One  may  represent  it  by  curve  i, 
showing  the  rate  of  learning  to  write  upon  a  typewriter, 
given  in  Figure  28.  It  will  be  seen  that  progress  is  step- 


2Q2 


ESSENTIALS    OF   PSYCHOLOGY 


wise  all  through  the  test.  First,  there  is  a  rapid  increase 
in  skill  during  the  period  when  the  elements  are  being 
learned,  then  there  is  a  period  without  progress,  then 
another  rise,  and  so  on.  There  are  alternations  of  rapid 


lioo 

1050 
IOOC 
950 
300 
650 
800 
750 


700 


650 


600 
550 


500 
450 


350 


A 


B 


AA 


O     as     30     35     *0     45      SO 


FIG.  28.  —  Curve  of  learning  to  write  on  the  typewriter.  The  horizontal  distances 
show  the  days  of  practice ;  the  vertical,  the  number  of  words  written  in  an  hour. 
Curve  i  gives  the  progress  during  the  original  practice ;  curve  2,  the  results  of 
nine  days'  practice  after  an  interval  of  two  years  and  thirty-five  days.  (From 
Swift :  '  Memory  of  Skillful  Movements,'  Psychological  Bulletin,  vol.  iii,  p.  186.) 


ACTION   AND   WILL  293 

improvement  with  levels  of  practice  without  improve- 
ment. These  level  parts  of  the  curve  have  been 
called  the  plateaus.  It  should  also  be  noted  that  in  the 
first  part  of  the  experiment  the  curve  is  much  steeper  than 
later.  One  gradually  approaches,  but  never  absolutely 
reaches,  the  highest  performance  of  which  the  individual 
is  capable. 

The  mechanism  of  learning  and  the  explanation  of  the 
course  of  learning  are  also  fairly  well  agreed  upon.  In  the 
first  place,  methods  by  which  improvement  is  made  are 
seldom  conscious.  One  falls  into  -good  habits  and  gives  up 
bad  habits  with  no  knowledge  of  how  or  why.  The  man 
does  his  best  all  the  time,  and  at  times  he  improves,  at 
times  he  continues  upon  the  same  level ;  he  himself  can- 
not tell  how  the  improvement  was  brought  about.  He 
does  not  ordinarily  plan  out  the  improvement ;  he  hits 
upon  it  by  chance.  More  interesting  and  consequently 
more  discussed  is  the  explanation  of  the  plateaus  in  the 
learning  curve  and  the  reasons  for  rising  from  one 
curve  to  another.  All  seem  to  agree  that,  during 
the  period  of  no  improvement,  associations  are  being 
formed  that  are  to  be  useful  at  a  later  stage  of 
learning.  One  can  advance  to  a  certain  stage  only 
on  the  basis  of  one  definite  group  of  habits.  When 
this  stage  has  been  reached,  no  further  advance  is 
possible  until  new  habits  have  been  thoroughly  estab- 
lished. During  the  time  one  keeps  to  the  plateau  the 
habits  are  being  stamped  in.  After  they  have  been 
thoroughly  established,  it  is  possible  to  go  on  to  higher 
acquirement.  Apparently,  the  learner  works  just  as  hard 
when  he  makes  no  progress  as  when  he  is  advancing. 


294          ESSENTIALS  OF  PSYCHOLOGY 

And  while  the  effects  of  the  work  do  not  show  in  the  ac- 
complishments, something  is  being  gained  all  the  time 
that  will  tell  finally  in  new  progress. 

Very  interesting  is  the  question  of  what  gives  the  sud- 
den rise  in  capacity.  Sometimes,  apparently,  it  is  the 
result  of  effort.  It  is  said  by  Bryan  and  Harter  that  a 
telegraph  operator  may  stay  for  years  at  a  small  office 
and  make  no  appreciable  gain  in  his  sending  or  receiving 
rate,  but  when  transferred  to  a  larger  office  where  more 
demands  are  made  upon  him,  he  will  suddenly  increase 
in  skill.  In  this  instance,  progress  is  the  result  of 
effort,  and  effort  of  increased  incentive.  But  all  effort  is 
not  rewarded  in  that  way.  If  one  strives  hard  for  a  new 
advance  before  the  habits  are  ripe,  the  result  usually  is  not 
advantageous ;  one  is  more  likely  to  disturb  the  ordinary 
habits  and  lose  efficiency  than  to  gain  new  skill.  Effort 
is  necessary  for  the  rise  to  a  new  level  of  speed,  but  effort 
is  harmful  before  the  necessary  amount  of  preparation  has 
been  made  by  fixing  old  habits.  The  advance  may  be 
accompanied  by  relaxation  of  effort ;  the  work  seems 
easier  when  the  advance  begins.  Another  element  that  is 
often  of  value  is  that  one  suddenly  becomes  clearly  con- 
scious of  the  methods  that  are  being  used,  and  of  the  es- 
sential part  of  the  responses  that  have  been  developed. 
It  is  the  rule,  in  learning  new  and  effective  combinations, 
that  they  are  hit  upon  blindly,  and  only  later  become 
consciously  recognised.  With  the  recognition,  one  is  ap- 
parently prepared  for  a  new  advance.  But  the  actual  im- 
provement that  gives  the  advance  is  ordinarily  some  new 
chance  combination  that  develops  unintentionally,  and  is 
not  appreciated  when  it  comes.  Another  factor  that  is 


ACTION   AND    WILL  295 

probably  as  important  as  the  acquirement  of  new  com- 
binations is  the  disappearance  of  bad  habits.  Failure  to 
advance  may  be  due  to  the  persistence  of  some  unfortu- 
nate habit  that  was  hit  upon  early.  In  the  course  of  time 
this  bad  habit  may  disappear,  and  the  record  will  jump 
up  suddenly  to  a  new  level.  Both  the  development  of  a 
new  and  advantageous  habit  or  set  of  habits,  and  the  dis- 
appearance of  some  bad  habit  that  has  been  retarding 
advance,  are  unconscious.  They  are  not  planned  in  ad- 
vance of  their  appearance,  and  are  not  recognised  when 
they  appear.  All  that  can  be  said  of  the  method  of  ac- 
quiring skill  is  that  one  must  continue  to  work  up  to  his 
best  capacity,  and  must  be  constantly  on  the  lookout  for 
any  new  method  that  may  promise  advance;  but,  in 
spite  of  one's  best,  there  will  always  be  periods  of  appar- 
ently fruitless  effort,  plateaus  of  no  advance,  and  the 
advance  to  new  levels  will  come  unexpectedly  and  for  no 
assignable  reason. 

All  learning  is  by  the  same  law  of  chance  trials  and  se- 
lection of  the  suitable  movement  when  it  is  hit  upon  by 
chance.  The  first  learning  is  by  the  selection  of  move- 
ments that  are  connected  as  overflow  discharges  with  the 
original  instincts.  When  a  fair  number  of  these  have 
been  fully  established,  new  movements  are  acquired  by 
chance  variations  from  those  already  learned.  Finally, 
when  all  of  the  movements  that  are  involved  in  a  compli- 
cated set  of  activities  have  been  learned  and  one  desires 
merely  to  combine  them  in  the  best  possible  way  to 
obtain  speed  and  accuracy,  the  combinations  and  connec- 
tions are  again  developed  by  chance.  Ordinarily  one  does 
not  know,  either  before  or  after,  how  the  various  advances 


296  ESSENTIALS   OF   PSYCHOLOGY 

in  skill  are  made.  The  only  guide  that  consciousness  ex- 
erts on  the  learning  process  is  to  keep  the  movement 
directed  to  the  most  likely  place  and  to  be  alert  for 
the  satisfactory  movement  or  combination,  when  it 
makes  its  appearance.  This,  with  constant  striving 
to  obtain  some  result  and  to  repeat  the  result 
when  obtained,  is  all  that  can  be  done  toward 
learning.  In  time  it  is  bound  to  be  successful.  It 
should  be  added  that  learning  must  be  spontaneous. 
Unless  the  movement  is  made  by  the  individual,  no 
learning  results.  Animals  or  men  that  are  put  through 
movements  by  another  or  by  stimulating  the  muscles 
electrically  do  not  learn  them.  They  must  be  hit  upon 
in  the  course  of  intentional  effort ;  there  is  no  short  cut 
to  learning. 

The  second  question  is  how  movements  are  controlled 
when  once  they  have  been  learned,  why  one  movement 
rather  than  another  is  made  on  any  occasion.  It  fol- 
lows from  the  law  of  the  connection  of  motor  and  sen- 
sory nerves  that  control  of  movement  must  always  be 
primarily  control  of  idea  or  control  of  sensation.  The 
process  of  learning  is  to  associate  movement  with  a  sen- 
sory process ;  when  the  connection  has  been  established, 
the  movement  results  whenever  the  related  idea  or  sensa- 
tion dominates  consciousness.  The  immediate  antece- 
dent of  a  movement  is  ordinarily  an  idea.  In  speech,  the 
expression  follows  upon  the  thought  of  the  words.  In 
repetition  of  spoken  words,  the  expression  comes  when  the 
word  to  be  repeated  is  heard.  Similarly  in  writing  from 
dictation,  as  one  hears  the  words  the  hand  traces  them 
upon  the  paper.  The  writing  may  go  on  fairly  accu- 


ACTION   AND   WILL  297 

rately  when  no  attention  is  given  to  the  words.  The  stu- 
dent in  a  lecture  may  take  notes  without  knowing  much 
of  what  he  is  writing,  while  thinking  of  the  next  foot-ball 
game,  or  of  other  extraneous  matter.  The  connection 
between  the  auditory  region  and  the  motor  region  serves 
to  keep  the  hand  writing  properly,  whether  all  attention  is 
fixed  upon  the  movement  or  not.  The  immediate  ante- 
cedent of  the  movement  is  always  some  idea,  but,  in 
addition,  two  other  groups  of  sensory  processes  must  co- 
operate in  the  control  of  the  movement.  These  are,  in 
James's  terms,  the  remote  sensations,  sensations  from  the 
eye  or  ear,  and  the  resident  sensations,  from  the  muscles 
and  other  parts  of  the  moving  member.  As  one  writes, 
the  pen  is  guided  by  the  sight  of  the  movements  that  are 
made.  With  the  eyes  closed  or  in  the  dark,  writing  is 
very  uncertain.  In  speech,  the  ear  takes  the  place  of  the 
eye  as  guide.  One  modulates  the  voice  in  accordance 
with  the  sounds  that  come  to  the  ear.  The  deaf  speak  in 
monotonous,  badly  modulated  tones  because  they  cannot 
recognise  or  control  their  speech  by  the  ear.  Deaf  chil- 
dren are  dumb  because  there  is  no  incentive  to  speak,  and 
because  they  have  no  pattern.  They  can  learn  only 
when  they  are  taught  to  control  the  movements  of  the 
speech  organs  by  touch.  Education  of  the  deaf  in  the  art 
of  speaking  is  necessarily  a  slow  process.  They  must  be 
taught  to  reproduce  the  movements  of  the  teacher's 
mouth  and  larynx  as  they  feel  them  or  see  them  in  the 
glass.  After  they  have  been  reproduced  by  chance,  the 
idea  of  the  word,  however  it  may  be  presented,  will  lead 
to  the  reinstatement  of  the  movement.  The  control  of 
the  movement  must  be  by  the  sensations  that  come  from 


298  ESSENTIALS   OF   PSYCHOLOGY 

the  moving  muscle.  This  never  becomes  as  adequate 
as  the  control  that  is  exerted  by  the  ear  of  the  normal  in- 
dividual. The  deaf  child  always  is  deficient  in  intonation 
and  modulation. 

In  addition  to  these  impressions  from  the  higher  senses, 
sensations  from  the  moving  member  serve  to  control  the 
movement.  This  statement  is  best  substantiated  by  the 
fact  that  where  the  kinaesthetic  sensations  are  wanting, 
control  is  inadequate.  As  the  result  of  disease,  sensa- 
tions from  the  muscles  are  not  infrequently  lacking,  and, 
in  these  patients,  movements  do  not  follow  the  ideas,  or  do 
not  follow  them  accurately.  Tabetic  patients,  patients 
who  through  disease  have  lost  the  sensory  tracts  of  the 
cord,  may  intend  to  make  a  movement  and  have  the  ap- 
propriate idea,  but  the  movement  will  not  follow,  or  will 
be  weak,  or  entirely  misdirected.  A  child  whose  sensory 
nerves  in  the  organs  of  speech  have  not  developed  will  not 
learn  to  talk  unless  special  methods  are  devised,  and  then 
will  learn  slowly  and  imperfectly.  The  sensations  from 
the  muscles  and  the  moving  parts  are  constantly  coming 
in  to  exert  an  influence  upon  the  amount  and  character 
of  the  motor  discharge.  They  adjust  the  movement  to 
the  position  of  the  member  at  the  moment,  and  exert  a 
general  guidance  upon  the  movement. 

Each  of  these  directing  and  controlling  factors  may  be 
explicit,  or  it  may  be  implicit ;  it  may  be  conscious  or 
unconscious,  or  vaguely  conscious.  It  has  been  asserted 
at  different  times  that  the  idea  that  initiates  thought 
must  be  a  kinaesthetic  memory  of  the  act,  that  it  must  be 
a  picture  of  the  member  in  a  certain  position,  or  any  one 
of  several  definite  ideas  or  images.  The  more  the  ante- 


ACTION   AND    WILL  299 

cedents  of  action  are  observed,  however,  the  more  evi- 
dent it  becomes  that  the  directing  idea  may  be  any  sort 
of  image  whatever.  In  many  cases,  the  imagery  is  very 
indefinite,  seems  to  be  very  largely  lacking.  It  may  be 
a  mere  thought  that  it  is  desirable  to  do  a  certain  thing ; 
it  may  be  any  part  of  the  act  to  be  performed.  In  other 
cases,  one  may  make  up  one's  mind  to  do  a  certain  thing 
at  a  certain  time,  and  when  the  time  comes,  it  is  done 
with  no  appreciable  idea  whatever.  The  expected  sen- 
sation starts  the  movement  decided  upon  without  any  idea 
or  intention  intervening.  Thus,  at  the  moment  you 
read  these  lines,  we  may  imagine  that  you  decide  to  under- 
line them.  You  may  think  of  the  position  your  hand 
should  take  to  bring  the  pencil  to  the  proper  point  on  the 
page,  and  you  may  think  of  this  position  in  kinaesthetic 
imagery  or  in  visual  imagery ;  you  may  think  merely  in 
words, '  I'll  underline  that,'  and  draw  the  line  with  no  fur- 
ther imagery  whatever.  Again,  you  may  have  decided 
at  the  beginning  of  the  reading  that  you  will  underline  the 
passages  that  are  important,  and  now  think  nothing  more 
than,  'this  is  important,'  and  have  the  movement  start 
at  once.  The  general  rule  is  that  there  is  more  imagery 
the  first  time  a  movement  is  made,  and  that  the  imagery 
decreases  in  amount  the  more  frequently  the  movement 
is  repeated.  In  general,  too,  each  part  of  the  movement 
is  preceded  by  a  separate  idea  at  first,  while,  after  several 
repetitions,  all  that  is  necessary  is  to  think  of  some  part  of 
the  movement  or  of  something  that  makes  the  movement 
desirable,  and  it  is  executed  without  further  outlining 
of  the  details.  Such  a  general  thought  as,  '  that  is  impor- 
tant,' is  the  usual  cue  for  the  more  familiar  movements. 


300  ESSENTIALS   OF   PSYCHOLOGY 

The  controlling  sensations,  resident  and  remote,  act 
even  less  consciously.  As  one  underlines,  one  is  aware 
through  the  eyes  of  the  course  of  the  movement ;  he  sees 
the  lines  grow,  but  he  does  not  realise  that  these  visual 
impressions  play  any  important  part  in  the  control.  The 
control  is  not  conscious  and  deliberate.  One  does  not 
first  appreciate  the  visual  sensations,  and  then  decide  in 
terms  of  them  how  the  pencil  must  move  to  make  the  line 
straight.  One  occasionally  notices  that  the  line  is  getting 
crooked  and  consciously  corrects  it ;  but,  if  all  goes  well, 
the  only  way  of  being  sure  that  sight  is  guiding  the  move- 
ment is  to  find  that  one  cannot  draw  a  straight  line  with 
the  eyes  closed.  The  influence  of  sight  is  effective,  not 
only  in  determining  the  direction  and  character  of  the 
movement,  but  also  in  determining  its  force  or  intensity. 
One  of  the  most  striking  simple  instances  of  this  is  in  the 
illusion  of  the  pound  of  lead  and  the  pound  of  feathers. 
A  pound  of  feathers  seems  very  much  lighter  than  the 
pound  of  lead,  because  the  large  bulk  calls  out  a  strong 
motor  discharge  for  the  feathers,  and  the  small  bulk  of 
the  lead,  a  slight  motor  discharge.  In  consequence,  the 
feathers  are  lifted  very  rapidly,  the  lead  very  slowly. 
The  weight  that  rises  more  rapidly  than  was  expected 
seems  light,  the  weight  that  rises  more  slowly  than  was 
expected  seems  heavy.  For  our  present  purpose,  the 
important  phase  of  the  experiment  is  to  show  that 
motor  impulse  is  controlled  in  amount  by  remote  sen- 
sations. Sensation  may  overcome  knowledge.  If  one  is 
told  in  advance  that  one  object  is  light,  the  other  heavy, 
the  illusion  persists  on  lifting.  Even  when  told  that  each 
weighs  exactly  a  pound,  the  large  mass  still  calls  out  the 


ACTION   AND   WILL  301 

larger  impulse,  and  is  raised  the  more  rapidly.  Given 
only  the  intention  of  raising  the  weight,  the  motor  im- 
pulse is  determined  primarily  by  the  visual  appearance 
of  the  object  to  be  lifted ;  other  sources  of  knowledge  will 
be  disregarded.  The  same  sort  of  control  by  vision  may 
be  seen  in  many  other  movements.  In  speaking,  one 
unconsciously  adjusts  the  loudness  of  the  tone  to  the  dis- 
tance of  the  listener,  the  size  of  the  room,  etc.  In  making 
a  golf  stroke,  the  force  of  the  blow  is  guided  by  the  sight 
of  the  green,  together  with  the  unexpressed  estimate  of 
the  distance.  In  each  of  these  instances,  the  strength  of 
the  movement  is  closely  adapted  to  the  visual  impressions, 
and  the  only  requirement  for  the  adaptation  is  that  the 
weight  to  be  lifted  or  the  object  to  be  hit  be  definitely 
looked  at,  or  have  been  observed  just  before  the  move- 
ment. The  control  of  the  kinaesthetic  sensations,  the 
resident  sensations,  is  similarly  unconscious.  One  never 
thinks  of  them  unless  attention  is  especially  directed  tow- 
ard them,  and  even  then  one  is  more  likely  to  be  con- 
scious of  the  visual  interpretation,  to  think  of  the  motion 
of  the  member  in  remembered  visual  images,  than  in  terms 
of  the  kinaesthetic  sensations  themselves.  One  misses 
them  when  they  are  destroyed  by  disease,  but  does  not 
appreciate  them  when  present.  Three  elements,  then, 
combine  in  the  initiation  and  guidance  of  a  movement, 
(i)  The  general  idea  or  intention  to  move.  This  is  found 
in  the  thought  of  the  movement  or  of  the  end  to  be  at- 
tained. (2)  The  remote  sensations  from  eye  or  ear. 
(3)  The  resident  sensations  from  the  moving  member 
itself.  These  resident  and  remote  sensations  control  the 
direction  and  force  of  the  movements. 


302  ESSENTIALS  OF  PSYCHOLOGY 

If,  as  has  been  said,  the  immediate  antecedent  of  a  move- 
ment is  an  idea,  the  question  naturally  arises  why  all 
ideas  do  not  lead  to  movements  or,  more  particularly,  how 
it  is  possible  that  one  may  think  of  a  movement  without 
making  it.  One  may  think  of  saying  something  and  not 
say  it,  one  frequently  thinks  intently  of  an  act  without 
performing  it.  On  this  problem  much  discussion  has 
developed,  but  no  very  definite  answer  has  been  given. 
The  probability  is  that  there  is  no  particular  process  that 
comes  invariably  to  set  off  the  movement  after  it  has  been 
decided  upon,  but  any  one  of  a  number  of  different  cir- 
cumstances may  serve  as  the  final  determinant  of  the 
movement.  Of  these,  the  most  important  is  the  wider 
setting  in  which  the  idea  presents  itself.  If  everything  else 
in  the  situation  favours  the  movement,  it  will  be  made ; 
if  the  idea  of  the  moment  is  altogether  out  of  harmony 
with  the  act,  it  will  not  be  put  into  execution.  Thus,  if 
one  has  been  waiting  for  the  summons  to  dine,  one  goes 
immediately  to  the  table  when  it  comes ;  if  the  summons 
comes  in  the  midst  of  a  sentence  that  is  being  written, 
the  movement  will  at  first  be  thought  of  vaguely,  but 
nothing  will  happen.  Sometimes  there  may  be  a  con- 
tending image  or  idea  that  interferes  with  full  attention  to 
the  movement  itself,  or  there  may  be  other  considerations 
that  make  the  act  undesirable  at  the  moment.  When 
these  disappear,  the  act  results.  It  is  probable,  when 
everything  seems  ready  for  the  movement  but  it  is  not 
made,  that  the  explanation  is  to  be  found  in  an  inhibiting 
idea  that  is  not  completely  conscious,  or  in  some  vaguely 
conscious  consideration  that  blocks  the  path.  One  of  the 
places  to  study  the  play  of  these  forces  and  considerations  is 


ACTION    AND    WILL  303 

in  getting  up  in  the  morning,  which  is  made  much  of  by  Pro- 
fessor James,  and  which,  for  its  difficulty,  seems  to  appeal 
to  nearly  everyone.  When  the  alarm  goes  off,  one  intends 
to  get  up,  one  even  thinks  of  the  movements  that  are  to 
be  made  in  their  order,  but  nothing  happens.  Sometimes 
one  suddenly  recalls  the  task  that  must  be  finished  early 
in  the  morning.  That  gives  the  required  impetus,  and  the 
various  habitual  movements  are  begun.  Often,  however, 
one  thinks  of  nothing  new ;  there  seems  no  particular  in- 
centive to  the  movements  just  before  they  begin ;  one 
finds  one's  self  dressing  and  that  is  all  that  there  is  to  the 
whole  matter.  In  cases  such  as  that,  it  is  probable  that 
the  act  begins  when  some  inhibiting  or  blocking  idea  dis- 
appears or  is  forgotten,  that  the  movement  is  due  to  the 
removal  of  a  check  rather  than  to  the  appearance  of  a 
new  force.  In  brief,  it  is  probable  that  the  movement  is 
due,  not  merely  to  the  idea  that  may  be  regarded  as  the 
motive,  but  to  the  entire  mental  context  at  the  moment, 
to  a  large  number  of  elements  that  constitute  the  situa- 
tion and  the  attitude  toward  the  situation.  In  any  case 
the  release  of  the  movement  does  not  follow  upon  any 
definitely  assignable  mental  content,  but  is  the  outcome 
of  a  whole  mass  of  considerations  that  combine  to  make 
the  act  desirable. 

The  rudiments  of  action  are,  then,  comparatively  simple. 
One  acquires  the  possibility  of  moving  by  random  move- 
ments that  give  a  pleasant  result,  and  the  connection  be- 
tween the  idea  of  the  movement  or  its  result,  and  the  move- 
ment is  established  by  frequent  repetition.  At  all  later 
times,  that  movement  may  be  made  whenever  the  idea  of 
the  movement  or  its  result  comes  to  consciousness.  The 


304  ESSENTIALS    OF   PSYCHOLOGY 

more  complex  problems  of  action  are  really  problems  in 
the  control  of  ideas.  What  one  ordinarily  calls  will  is 
exerted  primarily  in  the  control  of  the  course  of  thought, 
and  action  follows  when  the  proper  thought  presents 
itself.  The  problem  that  has  given  rise  to  the  most  dis- 
cussion in  connection  with  will  is  why,  when  alternative 
lines  of  action  present  themselves,  one  is  decided  on  rather 
than  the  other.  This  is  the  problem  of  choice.  This 
phase  of  the  problem  of  action  is  ultimately  not  a  problem 
of  movement,  but  of  thinking,  of  ideas.  What  is  chosen 
is  not  the  movement  as  such,  but  an  idea;  either  the 
result,  or  the  thought  of  the  movement  dominates  con- 
sciousness at  the  moment  of  choice.  When  either  com- 
pletely dominates  consciousness,  the  action  results. 
Control  of  action  offers  nothing  that  has  not  been  earlier 
discussed  in  connection  with  the  control  of  ideas,  or  with 
attention,  —  the  selection  of  sensations.  The  impor- 
tance of  action,  however,  makes  it  desirable  to  study  the 
old  laws  in  the  new  application. 

When  making  a  choice  between  two  courses  of  action,  one 
thinks  of  the  probable  results  of  each  and  chooses  the  one 
which  offers  the  greater  probability  of  a  pleasant  outcome, 
or  the  prospect  of  the  more  pleasant  outcome.  If  after 
class  it  is  a  question  between  going  home  or  to  a  shop, 
you  do  not  decide  on  the  movement  as  such,  but  you 
decide  that  it  is  necessary  to  finish  the  task  at  home  at 
once,  while  your  purchases  may  wait  until  later  in  the  day. 
When  this  decision  has  been  made,  the  necessary  move- 
ments are  begun  at  once.  The  same  holds  of  the  more 
complex  life  problems.  Choice  of  a  profession  where 
there  is  opportunity  for  choice  in  the  matter  at  all  is  a 


ACTION   AND   WILL  305 

choice  of  ends.  The  advantages  and  disadvantages  of 
each  profession  are  weighed  and  compared  with  the  diffi- 
culties that  must  be  overcome  in  obtaining  a  preparation 
for  each.  When  a  balance  has  been  struck,  it  finds  ex- 
pression in  some  phrase,  such  as,  '  this  will  be  my  life- 
work;  '  from  that  time  the  first  step  toward  the  entrance 
upon  the  profession  is  kept  in  mind,  ready  to  be  translated 
into  action  when  occasion  arises.  The  idea,  and  the  idea 
alone,  is  chosen  at  the  moment;  translation  into  action 
may  be  delayed  for  years. 

If  we  turn  back  to  ask  what  it  is  that  makes  one  line  of 
action  attractive  and  the  other  repulsive,  one  can  do  no 
more  than  enumerate  the  elements  in  heredity,  education, 
or  present  mood  that  make  the  results  of  one  line  of  con- 
duct on  the  whole  pleasant,  the  other  unpleasant  or  less 
pleasant.  In  action  as  in  attention  two  classes  are  to  be 
distinguished,  —  one  due  to  interest,  the  other  to  duty. 
Certain  things  are  pleasant  in  the  doing;  others  are  un- 
pleasant at  the  moment,  although  in  the  final  outcome 
highly  pleasant.  The  one  sort  of  action  is  said  to  be  in 
accordance  with  desire,  the  other  to  arise  from  duty. 
Desires  grow  out  of  hereditary  tendencies  and  experience, 
and  change  with  the  mood  and  attitude.  Duties,  on  the 
other  hand,  come  mostly  from  social  influences,  from 
ideals,  and  are  relatively  permanent.  The  actions  from 
desire  promise  immediate  pleasures ;  actions  from  duty 
give  pleasures  in  the  more  remote  future.  The  outcome 
of  the  line  of  action  chosen  always  seems  at  the  moment 
of  choice  to  promise  the  greatest  amount  of  pleasure,  im- 
mediate or  remote.  The  only  difference  is  that  the  pre- 
liminaries are  in  the  one  case  irksome  or  even  disagreeable, 


306  ESSENTIALS   OF   PSYCHOLOGY 

while  in  the  other  they  are  pleasant  even  though  the 
final  outcome  be  not  so  pleasant.  The  conditions  of  non- 
voluntary  attention  are  the  conditions  of  desire ;  the  con- 
ditions of  voluntary  attention  are  the  conditions  of  duty. 
Concretely,  if  one  ask  why  last  night  one  continued  at 
a  game  instead  of  turning  to  work  at  the  accustomed  hour, 
the  answer  would  be  found  in  the  instinctive  pleasure  in 
the  game,  or  in  the  pleasure  of  the  society,  or  in  the 
excuse  derived  from  experience  that  the  fatigued  condi- 
tion would  make  study  at  that  time  prejudicial  to  good 
work  on  the  morrow.  The  first  two  occasions  for  the 
decision  lead  back  to  heredity,  to  instinct,  while  the 
latter  is  an  expression  of  experience.  Suppose  that  the 
game  had  been  given  up  and  one  had  turned  to  work, 
the  explanation  would  be  found  in  social  pressure, 
in  the  dominance  of  ideal  or  remote  pleasures  over 
the  instinctive  and  experiential.  One  would  have  con- 
sidered the  unpleasantness  of  confessing  ignorance  before 
fellow-students,  or  one  would  have  had  in  mind  the  de- 
sire to  stand  well  at  the  end  of  the  college  course,  or 
would  have  considered  the  importance  of  that  lesson  for 
success  in  the  chosen  profession,  or,  still  more  remotely, 
one  may  have  developed  an  ideal  of  doing  well  everything 
that  is  required.  Even  this  last  ideal  probably  has  a 
social  origin,  although,  after  social  approval  has  rewarded 
action  in  harmony  with  that  ideal  or  punished  depar- 
tures from  the  ideal  sufficiently  often,  action  in  accord- 
ance with  it  becomes  a  habit,  and  there  is  ordinarily  no 
thought  at  the  moment  of  the  decision,  either  of  the  ideal 
or  the  consequences  of  the  action.  One  turns  to  work  be- 
cause one  feels  that  one  must,  because  one  feels  uncom- 


ACTION   AND   WILL  307 

fortable  if  the  game  is  not  given  up.  To  perform  the 
accepted  and  acknowledged  duty  is  essential  to  immediate 
comfort.  The  factors,  then,  that  determine  choice  are, 
on  the  one  hand,  the  instincts  of  the  individual  corrected 
by  his  experience,  immediate  and  remote ;  and,  on  the 
other,  ideals  derived  from  society.  Ultimately  the  social 
factors  go  back  to  experience,  so  that  one  may  assert 
that  choice  is  the  outcome  of  instinct  and  experience. 
Conflict  of  desires  is  merely  conflict  between  motives  de- 
veloped in  experience  or  heredity,  each  of  which  tends  to 
make  a  corresponding  course  of  action  desirable. 

The  conflicts  that  are  most  important  and  most  em- 
phasised are  those  between  instincts  and  instinctively 
pleasant  habits,  on  the  one  hand,  and  ideals,  on  the  other. 
On  the  whole,  it  seems  at  first  that  the  acts  that  are  fa- 
voured by  instinct  are  low  and  unworthy,  while  the  acts 
that  are  imposed  by  society  and  ideals  are  high  and  moral. 
The  opposition  is  only  apparent.  Some  of  the  acts  that 
are  in  themselves  noblest,  such  as  self-sacrifice,  are  in- 
stinctive, while  society  has  endeavoured  at  times  to  enforce 
altogether  unworthy  ideals.  The  occasion  for  the  ap- 
parent conflict  is  that  the  sorts  of  action  that  society 
imposes  against  instinct  need  all  of  the  social  enforcement 
possible,  while  the  instincts,  good  and  bad  alike,  are  strong 
enough  to  take  care  of  themselves.  Society  imposes 
rules  where  instincts  are  insufficient,  or  have  in  practice 
proved  undesirable,  or  less  desirable  than  a  method  of 
conduct  that  has  grown  up  through  trial  and  error  and 
been  transmitted  from  generation  to  generation  through 
tradition  and  social  institutions.  Where  instinct  and 
tradition  and  social  institutions  come  into  conflict,  all 


308  ESSENTIALS   OF   PSYCHOLOGY 

the  force  of  public  sentiment  is  necessary  to  enforce  tradi- 
tional and  conventional  acts  against  instinct.  In  conse- 
quence, a  premium  is  put  upon  them  by  calling  them  high 
and  noble,  while  the  instincts  are  "either  considered  un- 
worthy or  are  taken  for  granted.  As  a  matter  of  fact,  in- 
stincts mark  out  only  the  rough  outlines  of  conduct.  The 
limits  to  instinct,  or  the  demarkation  of  one  necessary  in- 
stinct from  another,  is  not  given  in  the  instinct,  but  must  be 
learned  by  the  individual  or  society.  We  have  selfish  and 
altruistic  instincts,  but  there  is  nothing  in  instinct  to  show 
how  far  one  should  be  selfish,  and  how  far  sympathetic  on 
particular  occasions.  These  checks  and  balances  must 
arise  through  social  intercourse.  •  When  they  have  de- 
veloped, they  are  just  as  important  for  the  survival  of  the 
social  group  as  are  the  instincts  themselves.  These 
checks  and  limitations  to  instinct  that  are  enforced  by 
social  pressure  are  said  to  constitute  duties,  as  opposed  to 
desires  which  are  largely  instinctive.  Choice,  then,  is 
always  a  choice  of  a  result;  and  often  one  finds  that 
choice  is  the  outcome  of  a  conflict  of  desires  with  duties, 
of  instincts  against  ideals.  At  other  times,  choice  is 
nothing  more  than  a  weighing  of  the  alternative  methods 
of  attaining  an  end  that  is  approved  both  by  desire  and 
duty.  Decision  is  in  terms  of  past  experience.  The  end 
that  has  proved  most  successful  in  the  past  or  that  prom- 
ises best  in  the  light  of  the  knowledge  of  the  agent  will  be 
chosen  and  will  result  in  action. 

So  far  we  have  not  made  use  of  the  word  '  will,'  although, 
in  popular  and  much  scientific  discussion,  will  is  the  word 
used  most  frequently  to  explain  action.  Will,  as  Angell 
says,  is  merely  a  word  to  designate  the  whole  mind  active. 


ACTION   AND   WILL  309 

Will  may  be  defined  as  the  sum  of  the  conditions  of  choice. 
It  is  the  outcome  of  the  entire  original  disposition  of  the 
individual,  together  with  its  modifications  by  experience. 
It  is  no  new  force  or  thing ;  it  is  the  application  to  the 
control  of  action  of  all  the  influences  that  earlier  we  have 
seen  to  control  attention,  perception,  and  the  course  of 
ideas.  Even  here,  these  forces  control  attention  and 
ideas  first,  and  control  action  only  as  they  control  atten- 
tion and  thought ;  but  since  action  is  practically  the  most 
important  or  at  least  the  most  striking  psychological  phe- 
nomenon, the  term  '  will '  is  usually  reserved  for  action. 
Ordinarily  will  is  not  applied  to  all  of  these  forces,  but  is 
reserved  for  the  ideals  that  enforce  social  traditions  and 
laws.  When  one  acts  under  the  control  of  an  ideal  or  for 
the  accomplishment  of  a  remote  end,  one  is  ordinarily 
said  to  have  performed  a  voluntary  act ;  when  one  gives 
way 'to  a  desire  of  an  instinctive  nature,  one  is  said  to  have 
acted  on  impulse.  On  the  other  hand,  one  is  said  to  have 
acted  voluntarily,  if  the  act  that  corresponds  to  the  ideal 
has  been  deliberately  weighed  against  the  desire,  and 
then  desire  has  won.  In  general,  voluntary  acts  are 
those  which  grow  out  of  a  conflict  between  instincts  and 
ideals,  in  which  ideals  prevail. 

Again,  one  may  see  in  the  application  of  the  terms 
strong  and  weak  will  the  tendency  to  identify  will  with 
control  by  ideals.  A  strong-willed  individual  is  one  who 
works  tenaciously  for  a  remote  good,  while  the  weak-willed 
individual  is  one  who  is  constantly  turned  aside  by  some 
momentary  desire.  Tenacity  in  holding  to  a  purpose  is 
probably  inherited;  the  character  of  the  purpose  is  the 
outcome  of  training.  The  strong-willed  individual  may 


310          ESSENTIALS  OF  PSYCHOLOGY 

be  good  or  bad,  but  he  always  has  an  ideal  or  set 
of  ideals,  and  bends  all  of  his  acts  to  their  attain- 
ments ;  while  the  weak-willed  individual  is  controlled, 
not  by  his  ideals,  but  by  instincts  and  impulses  that 
are  excited  by  the  changing  factors  in  the  environ- 
ment. The  ideals  that  control  in  the  strong-willed 
man  are  developed  by  living  in  society;  they  are  very 
largely  the  ideals  of  the  particular  community  or  family 
in  which  the  individual  has  grown  up,  modified  and  en- 
larged by  the  wider  knowledge  of  the  individual  obtained 
in  any  way  whatever.  You  can  see  in  the  talk  of  the 
young  boy  the  ideals  of  his  parents.  Later  these  ideals 
are  modified  by  the  school  influences ;  still  later  by  his 
reading;  and  then  by  the  profession  that  he  chooses. 
Now  and  again,  as  the  result  of  thinking,  an  individual 
decides  that  the  ideals  of  the  community  are  wrong,  and 
sets  up  for  himself  some  modification  of  the  ideals  of  the 
social  or  professional  community ;  but  important  varia- 
tions of  this  sort  are  relatively  rare,  and,  before  they  be- 
come of  value,  must  be  tested  and  accepted  by  the  wider 
social  group.  In  general,  the  ideals  of  the  individual  are 
the  ideals  of  his  community. 

Training  of  Will.  —  Training  will  is,-in  the  last  analysis, 
training  the  man.  Any  sort  of  learning  will  have  its  in- 
fluence upon  action.  The  more  one  knows,  the  better 
one  can  act,  and  training  for  action  cannot  be  separated 
from  training  of  any  other  kind.  Three  topics  may  be 
discussed  hi  this  connection  as  having  particular  bearing 
upon  the  problem.  First,  we  may  say  that  choice  is  very 
frequently  a  matter  of  habit.  If  one  of  two  alternative 
lines  of  conduct  has  been  chosen  once,  that  decision,  if 


ACTION  AND   WILL  311 

the  outcome  be  satisfactory,  will  make  the  same  choice 
probable  under  the  same  circumstances  in  the  future.  In 
the  adult  most  choices  are  of  this  habitual  kind.  One  no 
longer  hesitates  between  work  and  exercise.  During  the 
period  habitually  devoted  to  work,  one  ordinarily  declines 
invitations  to  a  game  ;  when  invited  to  walk  at  the  hour 
for  exercise  one  accepts  just  as  immediately.  One  de- 
clines to  consider  investments  that  are  suggested  by  the 
canvasser  at  the  door,  or  which  come  from  certain  firms 
that  for  some  time  have  been  sending  questionable  circu- 
lars. In  short,  most  of  the  decisions  of  to-day  were  set- 
tled by  decisions  of  the  same  kind  made  years  ago.  One 
moral  decision  strengthens  a  man  to  resist  similar  tempta- 
tions in  the  future,  and  a  large  number  of  decisions  of  the 
sort  makes  it  practically  impossible  for  him  to  decide  in  the 
wrong  way.  On  the  other  hand,  when  a  man  decides  to 
do  wrong,  he  makes  future  right  conduct  in  that  respect 
more  difficult,  and  each  immoral  act  makes  more  difficult 
the  reformation. 

A  second  important  phase  of  training  will  is  in  develop- 
ing a  system  of  ideals.  This  can  be  done  only  indirectly. 
Ideals  come  unconsciously  from  the  society  in  which  the 
child  is  brought  up.  If  the  boy  finds  that  his  father  and 
older  brothers  constantly  disapprove  of  certain  acts  and 
approve  of  others,  he  takes  their  approval  for  law ;  their 
ideals  become  his  ideals.  The  effective  moral  ideals 
come  from  the  approval  of  groups  and  classes.  As  may 
be  seen  in  any  community,  right  and  wrong  are  made  by 
public  sentiment,  not  by  law.  A  law  is  respected  only  so 
far  as  it  is  backed  by  public  sentiment.  This  holds  for 
moral  laws  as  well  as  of  statutory  enactments.  Develop- 


312  ESSENTIALS   OF   PSYCHOLOGY 

ment  of  ideals  is  largely  through  social  approval  and 
disapproval  of  the  acts  and  expressions  of  the  child. 
Proper  ideals  can  be  developed  by  placing  the  child  in  the 
proper  social  atmosphere,  and  in  no  other  way.  This 
atmosphere  is  most  effective  when  it  comes  from  actual 
contact  with  people.  Books  and  reading  and  direct 
exhortation  may  gradually  have  an  effect;  but  unless 
you  can  make  the  child  feel  that  the  class  to  whom  the 
ideals  belong  is  actually  his  class,  reading  and  precept 
are  of  little  value. 

A  third  difficulty  is  to  make  the  individual  act  up  to  the 
knowledge  and  ideals  that  he  possesses.  Every  once  in  a 
while  one  observes  an  individual  who  knows  the  right 
and  approves,  but  does  wrong.  The  only  cure  for  this 
condition  is  to  develop  a  habit  of  action.  This  can  be 
done  most  effectually  by  making  the  child  appreciate 
the  advantages  of  action  and  the  disadvantages  of  in- 
action. An  individual  left  to  take  the  natural  conse- 
quences of  his  acts  will  soon  develop  a  habit  of  doing  the 
thing  that  he  sees  should  be  done,  at  the  time  that  it 
should  be  done.  It  is  only  the  individuals  who  are  pro- 
tected from  the  consequences  of  inaction  and  indecision 
who  continue  inactive  in  the  face  of  acknowledged  duties. 
If  a  habit  becomes  established,  there  is  no  longer  question 
whether  a  thing  shall  be  done  or  not;  the  situation  at  once 
evokes  a  decision,  and  the  decision  evokes  the  act.  Train- 
ing will  consists  in  establishing  habits  and  in  developing 
ideals.  All  training  of  whatever  sort  is  bound  to  develop 
both  habits  and  ideals ;  training  of  will  cannot  be  dis- 
tinguished from  training  the  man  as  a  whole. 

This  discussion  of  action  adds  but  one  essential  fact 


ACTION   AND   WILL  313 

to  the  list  that  has  been  developed  in  the  earlier  chapters. 
This  is  that  a  movement  associated  with  an  idea  is  made 
whenever  that  idea  dominates  consciousness.  The  move- 
ment is  either  associated  with  the  idea  or  sensation  at 
birth  as  in  instinct,  or  becomes  associated  with  it  through 
the  process  of  chance  trial.  The  control  of  action  is 
primarily  control  of  ideas  or  of  sensations.  The  classifi- 
cation of  actions  is  in  terms  of  the  way  the  connection 
was  brought  about,  whether  instinctive  or  acquired; 
in  terms  of  the  amount  of  consciousness,  reflex  and  auto- 
matic, as  opposed  to  impulses  and  voluntary  acts ;  and 
in  terms  of  whether  the  act  is  ultimately  controlled  by 
interest  (instinct  and  experience)  or  by  ideals.  This 
last  opposition  is  identical  in  its  criterion  with  the  divi- 
sion of  attention  into  non-voluntary  and  voluntary, 
or  with  the  division  of  thinking  into  controlled  and 
random.  In  each  case,  immediate  pleasure  attaches  to 
the  former,  effort  and  strain  to  the  latter.  In  the  one, 
pleasure  is  immediate,  in  the  other,  remote.  In  all  essen- 
tials, except  in  the  fact  that  movement  follows  upon  idea, 
the  laws  of  action  are  the  laws  of  attention  and  percep- 
tion, and  of  reasoning. 

EXERCISES 

i.  Try  to  develop  some  movement  that  is  latent.  Try,  for  ex- 
ample, to  wink  your  right  eye  without  closing  the  left.  Keep  a  rec- 
ord of  the  number  of  trials,  and  watch  the  spread  of  the  contraction 
from  a  neighbouring  muscle.  First  try  keeping  attention  fixed  upon 
the  eye  to  be  kept  open,  then  upon  the  eye  to  be  closed  while  the 
other  is  neglected.  Which  is  the  more  effective  ?  If  the  movements 
of  the  eyelids  have  already  been  dissociated,  try  patting  your  chest 


314  ESSENTIALS   OF   PSYCHOLOGY 

with  one  hand  while  you  rub  the  top  of  the  head  with  the  other. 
Keep  the  same  records. 

2.  Trace  the  process  of  acquiring  skill  with  the  cup  and  ball. 
Keep  a  record  of  the  proportion  of  successes  over  a  period  of  several 
days.     Trace  plateaus  and  the  occasions  for  the  sudden  rises.     If 
more  convenient,  diabolo  or  any  other  simple  game  of  skill  may  be 
substituted  for  the  cup  and  ball. 

3.  Procure  two  objects  of  the  same  weight  but  of  unequal  size, 
and  try  to  train  yourself  to  lift  them  at  the  same  rate.     Can  you 
avoid  the  illusion  of  weight  or  rid  yourself  of  it  by  practice  ? 

4.  Try  writing,  while  with  hand  hidden  from  direct  observation 
you  watch  your  hand  in  a  mirror.     What  is  the  effect  ?    Which  of 
the  three  controls  mentioned  in  the  text  is  disturbed  in  the  experi- 
ment ?     Can  you  overcome  the  difficulty  with  practice  ? 

5.  Study  yourself  while   making  a  high  dive.     If   several  at- 
tempts are  necessary  before  you  start,  try  to  trace  the  immediate 
antecedent  of  the  action.     If  diving  be  impracticable,  observe 
getting  up  on  a  cold  morning,  or  getting  into  a  cold  bath. 

6.  Trace  out  the  instinctive,  experiential,  and  ideal  elements  in 
some  important  real  decision  that  you  make  during  the  day. 

REFERENCES 

JAMES:  Principles  of  Psychology,  vol.  ii,  ch.  xxvi. 

ANGELL  :  Psychology,  chs.  xx,  xxi. 

THORNDIKE  :  Animal  Intelligence.     Psych.  Rev.  Mon.  Sup.,  vol.  2. 

BAIR  :  The  Development  of  Voluntary  Control.     Psych.  Rev.,  vol.' 

8,  p.  474. 
PILLSBURY  :  Attention,  ch.  x. 


CHAPTER  XIV 
WORK,   FATIGUE,  AND  SLEEP 

FATIGUE  has  a  very  general  influence  upon  mental  and 
physical  efficiency.  It  modifies  behaviour  in  many  ways 
and  is  highly  important  for  mental  hygiene.  The  great 
value  of  an  accurate  knowledge  of  the  most  profitable 
periods  of  work,  the  relation  of  the  quantity  and  quality 
of  work  to  its  duration,  and  the  general  effects  of  work 
and  rest  upon  health  and  well-being  have  furnished  the 
incentive  for  numerous  investigations  of  fatigue,  par- 
ticularly in  the  last  two  decades.  While  it  cannot  be  as- 
serted that  agreement  has  been  reached  upon  all  points, 
it  seems  worth  while  to  summarise  the  results  so  far 
obtained,  because  of  their  wide  application  to  the  activi- 
ties of  everyday  life.  It  is  desirable  to  know  what  the 
maximum  efficiency  of  the  individual  is  in  each  respect. 
It  is  desirable  to  work  up  to  the  limit  of  capacity,  in  emer- 
gencies at  least,  and  even  more  important  to  be  sure  that 
the  limit  is  not  overpassed.  The  effects  of  overwork 
are  apparent  everywhere  to-day.  It  is  accepted  as  one 
of  the  important  causes  in  producing  nervous  wrecks 
and  certain  forms  of  insanity.  To  know  what  overwork 
is  and  to  know  how  to  avoid  it  is  evidently  highly  desir- 
able. 

The  Nature  and  Signs  of  Fatigue.  —  The  first  question 
is,  what  is  fatigue  and  what  its  nervous  and  mental  mani- 
315 


31 6  ESSENTIALS   OF   PSYCHOLOGY 

festations?  In  general,  fatigue  may  be  denned  as  the 
decreased  capacity  for  doing  work  that  comes  as  a  result 
of  work.  Mentally  it  is  usually  accompanied  by  sensa- 
tions that  are  in  some  measure  an  index  of  the  degree  of 
fatigue.  It  is  not  possible  to  identify  feelings  of  fatigue 
with  fatigue  itself,  as  will  be  seen.  One  feels  tired  when 
one's  capacity  is  unimpaired.  Physiologically  it  has  been 
demonstrated  that  fatigue  is  accompanied  by  three  sorts 
of  changes.  First,  poisons  accumulate  in  the  blood  and 
affect  the  action  of  the  nervous  system,  as  has  been  shown 
by  direct  analysis.  Mosso  obtained  striking  results  by 
an  indirect  method  that  is  not  altogether  free  from  crit- 
icism. He  selected  two  dogs  as  nearly  alike  as  possible. 
One  he  kept  tied  all  day,  the  other  he  exercised  until  by 
night  it  was  thoroughly  tired.  Then  he  transfused  the 
blood  of  the  tired  animal  into  the  veins  of  the  rested 
one  and  produced  in  him  all  the  signs  of  fatigue  that 
were  shown  by  the  other.  There  can  be  no  doubt 
that  the  waste  products  of  the  body  accumulate  in 
the  blood  and  interfere  with  the  action  of  the  nerve- 
cells  and  the  muscles.  It  is  probable  that  these  accu- 
mulations come  as  a  result  of  mental  as  well  as  of 
physical  work. 

A  second  change  in  fatigue  has  been  found  in  the  cell 
body  of  the  neurone.  Hodge  showed  that  the  size  of  the 
nucleus  of  the  cell  in  the  spinal  cord  of  a  bee  diminished 
nearly  75  per  cent  as  a  result  of  the  day's  activity,  and 
that  the  nucleus  became  much  less  solid.  A  third  change 
that  has  been  demonstrated  as  a  result  of  muscular  work 
is  the  accumulation  of  waste  products  in  the  muscle 
tissue.  Fatigued  muscles  contain  considerable  percent- 


WORK,    FATIGUE,    AND    SLEEP 


317 


ages  of  these  products.  That  they  are  important  factors 
in  the  fatigue  process  has  been  shown  by  washing  them 
from  a  fatigued  muscle.  As  a  result  the  muscle  gains 
new  capacity  for  work.  The  experiments  are  performed 
on  the  muscles  of  a  frog  that  have  been  cut  from  the  body 
and  fatigued  by  electrical  stimulation.  When  they  will 
no  longer  respond,  their  sensitivity  may  be  renewed  by 
washing  them  in  dilute  alcohol  or  in  a  weak  salt  solution 


FIG.  2g.  —  Changes  of  nucleus  in  nerve-cells  as  a  result  of  fatigue.  (A)  and  (B) 
are  both  from  the  spinal  ganglion  of  a  cat.  (A)  shows  the  resting  condition, 
(B)  the  effects  of  stimulating  the  cell  electrically  through  its  nerve  for  five 
hours.  The  nuclei  in  (B)  are  seen  to  be  much  smaller  and  to  be  very  irregular 
in  outline.  (From  '  Amer.  Text-book  of  Physiology,'  Fig.  74.  after  Hodge.) 

that  will  dissolve  the  products  of  fatigue.  It  is  probable 
that  these  products  stimulate  the  sense-organs  in  the 
muscles  and  thus  give  some  of  the  sensations  of  fatigue. 
Of  these  physical  effects  of  fatigue,  the  accumulation  of 
the  waste  products  in  the  blood  and  the  effects  upon  the 
nerve-cells  are  probably  common  both  to  mental  and 
physical  fatigue.  The  effect  upon  the  muscles  plays  a 
part  in  mental  fatigue  only  so  far  as  all  mental  work 
involves  some  muscular  activity. 


318  ESSENTIALS   OF   PSYCHOLOGY 

The  Analysis  of  Mental  Fatigue.  —  More  practical 
are  the  results  of  the  experiments  accumulating  in  recent 
years  upon  the  actual  course  of  the  work.  The  change 
in  capacity  in  the  course  of  work  has  been  shown  to  be 
dependent  upon  a  number  of  factors  that  may  be  isolated. 
First  we  have  fatigue,  the  decreased  capacity  for  work, 
which  may  be  assumed  to  increase  regularly  with  the 
amount  of  work  accomplished.  But  this  decrease  in 
capacity  is  partly  obscured  by  another  effect  of  work  just 
as  well  established,  the  resulting  practice.  Every  bit 
of  work  not  only  diminishes  capacity  but  also  gives 
increased  efficiency  for  the  same  sort  of  work.  These 
two  factors,  practice  and  fatigue,  may  be  regarded  as 
always  present  and  always  opposed.  The  result  is  that 
each  obscures  the  effects  of  the  other.  When  work  first 
starts,  practice  increases  more  rapidly  than  fatigue,  and 
in  consequence  one  can  do  more  work  after  working  for 
a  little  time  than  was  possible  at  first.  The  course  of 
recovery  from  the  two  effects  is  very  different.  One 
recovers  from  fatigue  very  quickly.  It  is  ordinarily 
entirely  gone  after  a  night's  rest  and  begins  to  decrease 
appreciably  as  soon  as  a  task  is  finished.  On  the  other 
hand  the  effects  of  practice  persist  over  long  periods  of 
time.  Days  and  years  after,  some  of  its  influence  may 
be  noticed.  Two  other  factors  are  important  in  deter- 
mining the  course  of  the  practice  curve,  —  one  may  be 
called  mental  inertia,  the  other  the  incentive.  When 
one  first  starts  a  task,  work  is  difficult  and  slow ;  as  time 
goes  on,  work  gradually  increases  in  amount  and  accuracy. 
When  once  started,  work  proceeds  at  the  regular  rate  and 
stopping  may  be  difficult;  or  more  truly,  it  is  easier  to 


WORK,   FATIGUE,   AND    SLEEP  319 

continue  work  than  it  is  to  stop  and  begin  again.  Then 
one  may  distinguish  the  initial  and  final  incentive.  One 
works  very  much  harder  when  first  beginning  a  task  than 
later.  Toward  the  end  there  is  nearly  always  a  final 
spurt  that  again  increases  considerably  the  rate  of  work 
and  the  amount  accomplished.  Finally,  as  one  becomes 
accustomed  to  the  conditions,  one  works  to  better  ad- 
vantage than  when  first  beginning. 

The  Economical  Periods  of  Work.  —  The  most  eco- 
nomical period  of  work  is  that  in  which  one  gets  all  the 
advantages  of  continued  work  without  going  on  to  the 
point  of  fatigue.  It  is  of  course  impossible  to  give  any 
general  rules  that  will  apply  to  all  kinds  of  work  and  to  all 
people.  How  much  work  may  be  done  depends  upon  the 
nature  of  the  work  and  upon  the  strength  of  the  individ- 
ual. The  fact  that  one  does  more  after  working  for  a  little 
time  than  when  one  first  begins  holds  universally.  How 
long  one  should  continue  after  the  effects  of  fatigue  are 
greater  than  the  benefits  of  practice  depends  upon  the 
kind  of  work  and  the  practical  necessities  for  its  comple- 
tion. Fatigue  itself  is  not  to  be  avoided,  for  the  lesser 
degrees  wear  off  in  a  short  time  and  are  entirely  overcome 
by  a  night's  sleep.  The  poor  work  that  results  when 
fatigue  is  too  great  makes  effort  unprofitable,  and  the 
after  effects  in  the  form  of  overwork  may  have  such  se- 
rious results  as  to  put  a  premium  upon  avoiding  them  at 
all  reasonable  cost. 

The  Evidence  of  Fatigue.  —  How  to  know  when  one 
is  in  danger  of  permanent  injury  from  work  is  not  at  all 
easy.  Fatigue  shows  itself  by  sensations  of  different 
sorts,  some  from  tired  muscles,  some  of  a  more  indefinite 


320  ESSENTIALS   OF   PSYCHOLOGY 

character  from  the  inner  organs.  These  sensations, 
however,  are  not  very  certainly  associated  with  fatigue 
itself.  Often  one  feels  tired  when  actual  trial  shows  no 
marked  incapacity  for  work.  Rather  it  is  usual  for  the 
best  work  to  be  done  when  the  sensations  indicate  a  state 
of  bodily  inefficiency  before  work  is  begun.  Even  the 
capacity  for  doing  work  is  not  an  invariable  sign,  because 
it  is  not  unusual  to  be  able  to  do  good  work  when  the 
organism  is  fatigued  to  the  point  where  continued  work 
will  do  injury  of  a  permanent  character.  One  must  be 
guided  by  taking  into  consideration  three  factors,  —  the 
sensations  of  fatigue,  the  character  of  the  work  that  is 
done,  and  what  previous  experience  has  shown  to  be  the 
probable  after  effects.  It  is  usually  inadvisable  to  persist 
to  the  point  where  a  night's  rest  will  not  remove  fatigue  and 
restore  the  original  capacity.  Certainly  long-continued 
work  beyond  this  stage  is  bound  to  have  serious  con- 
sequences. 

The  Best  Period  for  Rest.  —  To  know  how  long  to 
rest  between  periods  of  work  is  as  important  as  to  know 
when  to  stop.  Results  of  experiments  indicate  that  the 
length  of  the  rest  that  should  be  introduced  between 
the  periods  of  work  depends  upon  the  length  of  the  pre- 
vious work  and  upon  the  character  of  the  work.  The 
rest  should  be  long  enough  to  permit  recovery  from  fatigue 
but  not  to  lose  the  mental  momentum.  After  long  pe- 
riods of  work,  two  hours  or  more,  the  most  advantageous 
intermission  is  approximately  fifteen  minutes;  for  rela- 
tively short  periods  five  minutes  has  proved  itself  most 
satisfactory.  Longer  periods  waste  too  much  time  and 
cause  a  loss  of  inertia  and  of  practice  that  is  not  com- 


WORK,   FATIGUE,   AND    SLEEP  321 

pensated  for  by  recovery  from  fatigue.  Shorter  rests 
merely  cause  loss  of  inertia  without  any  compensating 
rest. 

Change  of  Work  No  Rest.  —  Several  facts  that  have 
been  suggested  by  experiments  are  contrary  to  the  com- 
mon assumptions  of  many  people.  For  example,  it  is 
believed  usually  that  one  may  rest  through  change  of 
work,  —  that  if  one  has  been  tired  by  mental  work  of 
one  sort  it  is  not  necessary  to  rest  altogether,  but  by 
changing  to  something  else  one  may  become  rested 
through  the  change.  The  one  important  investigation 
on  this  point  indicates  that  the  everyday  assumption  is 
not  in  harmony  with  the  facts.  An  hour's  work  learning 
nonsense  syllables  followed  by  a  half  hour's  practice  on 
mental  arithmetic,  with  a  return  to  the  nonsense  syllables, 
rests  one  no  more  than  a  continued  period  of  nonsense 
syllables.  This  is  on  the  assumption  that  learning  non- 
sense syllables  is  no  more  difficult  than  mental  arithmetic. 
If  one  turns  from  a  more  difficult  to  an  easier  task,  one 
will  of  course  not  be  so  tired  as  if  one  had  continued  with 
the  more  difficult.  So  far  as  these  results  can  be  accepted, 
it  seems  that  all  sorts  of  mental  fatigue  are  of  the  same 
kind,  and  that  it  is  not  possible  to  rest  one  function  while 
exercising  another.  There  is  so  much  in  common  be- 
tween the  different  mental  operations  that  all  become 
tired  together.  It  is  possible  that  the  commonly  accepted 
opinion  to  the  contrary  is  due  to  the  greater  interest 
one  may  have  in  a  new  task.  One  ordinarily  turns  from 
a  task  only  when  obstacles  have  presented  themselves 
or  when  for  some  reason  the  work  has  become  uninterest- 
ing. It  is  possible  that  the  greater  interest  in  the  new 
y 


322  ESSENTIALS   OF   PSYCHOLOGY 

work  and  consequent  greater  effectiveness  are  mistaken 
for  recovery  from  fatigue. 

Mental  and  Physical  Fatigue  One.  —  Very  similar  is 
the  attitude  toward  the  problem  of  the  relation  between 
mental  and  physical  fatigue.  It  is  generally  believed  that 
one  may  rest  from  mental  work  while  exercising,  but 
experiments  indicate  that  capacity  for  mental  work  is 
decreased  by  physical  work  if  it  is  too  difficult.  If  one 
takes  a  vigorous  run  or  other  severe  exercise  between 
two  periods  of  the  same  sort  of  work,  as  in  the  experi- 
ments mentioned  above,  the  capacity  for  mental  work 
is  diminished  rather  than  increased.  Here  as  before  the 
effect  will  depend  upon  the  severity  of  the  task.  If  the 
exercise  be  mild,  one  will  rest  relatively  just  as  one  does 
during  less  difficult  mental  work.  In  fact  the  whole  ques- 
tion of  work  and  fatigue  is  relative,  as  one  never  rests 
absolutely  except  during  sleep,  and  even  then  there  is 
merely  gain  of  repair  over  waste,  not  absolute  quiescence 
of  all  functions.  The  identity  of  mental  and  physical 
fatigue  has  been  demonstrated  many  times,  both  that 
mental  work  induces  physical  fatigue  and  that  physical 
work  induces  mental  fatigue.  One  cannot  do  severe  men- 
tal work  effectively  after  a  hard  day  of  physical  labour, 
and  experiments  show  that  one  is  less  capable  of  physical 
after  hard  mental  work.  This  general  identity  of  mental 
and  physical  work  and  fatigue  is  being  recognised  by  the 
physician.  A  patient  suffering  from  overwork  as  a  result 
of  too  much  study  or  worry  is  no  longer  advised  to  take 
much  exercise,  but  is  put  to  bed  or  given  very  little  easy 
exercise.  Of  course  this  does  not  imply  that  exercise  is 
not  beneficial  in  health.  Exercise  is  essential  to  the 


WORK,   FATIGUE,   AND   SLEEP  323 

development  and  health  of  the  body,  and  needs  no  justi- 
fication. One  should  not  expect  to  be  able  to  work 
immediately  after  exercise,  but  in  the  long  run  the  effects 
of  exercise  are  beneficial. 

Morning  and  Evening  Workers.  —  Another  interesting 
result  of  recent  investigations  is  that  there  are  daily 
rhythms  of  capacity  for  work,  that  every  one  has  a  certain 
part  of  the  day  during  which  he  has  greater  capacity. 
According  to  one  authority,  men  divide  naturally  into 
morning  and  evening  workers.  The  one  group  are  at 
their  best  early  in  the  morning ;  the  other  group  do  not 
reach  their  full  capacity  until  toward  evening,  —  the 
amount  and  accuracy  of  their  work  increases  steadily 
through  the  day.  It  has  not  been  determined  whether 
the  difference  is  innate  or  the  result  of  habit,  but  in  an 
adult  accustomed  to  mental  work  one  habit  or  the  other 
is  always  readily  demonstrated,  even  if  the  individual 
himself  is  unaware  of  it.  Evidently  one  should  take 
advantage  of  the  daily  rhythm  by  devoting  the  best  part 
of  the  day  to  the  more  difficult  tasks. 

It  should  be  added  that  the  measurements  of  fatigue 
upon  which  these  statements  rest  are  derived  from  ordi- 
nary routine  work  under  no  particular  incentive  other 
than  to  do  one's  best.  It  is  certain  that  a  sufficiently 
strong  desire  would  at  any  stage  have  brought  the  rate 
of  work  back  to  the  maximum,  at  least  for  a  little  tune. 
Phenomena  of  this  kind  have  led  some  writers  to  argue 
that  fatigue  is  an  illusion.  That  what  is  called  fatigue 
is  really  ennui  or  boredom.  This  conclusion  overlooks 
the  very  evident  after  effects  of  severe  prolonged  work 
in  decreased  efficiency  over  considerable  periods  and  even 


324  ESSENTIALS   OF   PSYCHOLOGY 

in  diseased  nervous  conditions.  While  the  amount  of  work 
that  will  be  accomplished  depends  very  largely  upon  the 
incentive,  it  does  not  follow  that  fatigue  is  not  real  and  a 
factor  to  be  considered  in  the  arrangement  of  the  day's 
routine.  The  results  that  have  been  given  hold  for  the 
course  of  ordinary  work  where  the  incentive  is  constant  and 
not  particularly  strong.  If  the  incentive  is  increased,  the 
absolute  times  given  would  all  be  increased,  but  the  rela- 
tive values  would  still  remain  approximately  the  same. 
There  would  still  come  a  time  when  the  amount  and 
accuracy  of  the  work  would  be  reduced  to  a  point  where 
work  did  not  pay.  In  some  degree,  too,  the  after  effects 
of  the  work  increase  with  the  amount  of  work,  although 
probably  not  in  the  exact  ratio  of  accomplishment. 
Work  done  willingly  and  cheerfully  under  suitable  in- 
centives is  apparently  less  fatiguing  in  the  long  run  than  a 
smaller  amount  accomplished  under  unfavourable  condi- 
tions. One  may  even  agree  with  James  that  in  moments 
of  exaltation  one  may  perform  at  a  rate  far  above  the 
ordinary  level  without  permanent  injury,  and  at  the  same 
time  accept  the  results  of  experiments  under  ordinary 
conditions  as  a  guide  for  daily  life. 

Fatigue  Inevitable  and  in  Moderation,  Desirable.  — 
The  discussion  of  fatigue  and  the  methods  of  obviating 
it  is  likely  to  leave  the  impression  that  fatigue  is  some- 
thing to  be  avoided  at  all  hazard.  This  is  far  from  being 
the  case.  Fatigue  is  unavoidable  if  one  works,  and  work 
is  essential  to  any  sort  of  development.  As  was  said  in 
the  beginning,  work  has  two  effects,  fatigue  and  practice. 
Practice  remains  and  furnishes  the  endowment  of  the 
individual  for  all  later  work;  fatigue  disappears  after  a 


WORK,   FATIGUE,   AND    SLEEP  325 

night.  The  ordinary  net  effect  of  work  the  day  after  is 
an  increase  in  capacity.  The  general  effects  of  work  are 
altogether  desirable.  Fatigue  is  not  something  to  be 
avoided.  The  most  that  is  desirable  is  to  consider  the 
laws  of  fatigue  and  learn  to  work  to  the  best  advantage. 
The  aim  of  life  is  not  to  avoid  fatigue  but  to  accomplish 
as  much  as  possible  with  the  minimum  of  fatigue.  Fa- 
tigue is  undesirable  only  in  the  maximum  amounts,  only 
when  it  threatens  permanent  injury,  rather  than  when 
it  temporarily  reduces  capacity. 

Sleep.  —  Very  closely  connected  with  fatigue  in  prac- 
tice and  theory  is  sleep.  While  sleep  is  one  of  the  best 
known  phenomena  of  life,  it  is  also  one  of  the  least  under- 
stood. What  sleep  is  or  why  it  comes  on  is  as  yet  not  a 
matter  of  agreement.  Something  more  is  known  of  the 
course  of  sleep  and  we  may  begin  our  discussion  with 
that.  Several  experimenters  have  measured  the  depth 
of  sleep  at  different  times  during  its  course  by  deter- 
mining the  intensity  of  stimulus  required  to  waken  an  in- 
dividual. They  all  agree  that  sleep  increases  in  depth 
rapidly  during  the  first  three-quarters  of  an  hour  and 
then  decreases  gradually  during  the  remainder  of  the 
night.  It  has  been  suggested  that  the  recuperative 
processes  predominate  in  the  latter  part  of  the  period, 
when  sleep  has  passed  its  climax.  Why  one  goes  to 
sleep  is  not  so  easily  answered.  Obviously  sleep  has 
some  relation  to  fatigue,  but  over-fatigue  is  inimical  to 
sleep.  One  ordinarily  goes  to  sleep  most  readily  under 
monotonous  stimulation,  but  a  persistent  idea  if  more  ex- 
citing makes  sleep  impossible  when  all  else  is  favourable. 
Opinion  at  present  inclines  to  the  view  that  sleep  is  an 


ESSENTIALS   OF   PSYCHOLOGY 


instinct,  a  form  of  reaction  of  the  nervous  system  that  is 
induced  by  certain  definite  stimuli,  and  that  tends  also 
to  recur  somewhat  rhythmically.  This  response  is 
favoured  by  withdrawal  of  external  stimuli,  quiet  and 
darkness,  by  a  moderate  degree  of  fatigue,  by  relaxed 
or  dispersed  attention,  and  ordinarily  through  habit 


STRENGTH  OF  STIMULUS 
800 1 


100 


HOURS  OS     10     15    ZD     2.5   3.0    3.5     4.0    45    5.0    £5    G.O    6£>    7.0    7JS  7.8 

FIG.  30.  —  Curve  showing  the  depth  of  sleep  at  different  periods  after  going  to 
sleep.  The  figures  on  the  horizontal  line  show  the  time  since  going  to  sleep  ; 
those  on  the  vertical  line,  the  relative  height  from  which  a  ball  must  drop 
to  waken  the  sleeper.  (From  Howell :  'Physiology,'  Fig.  112,  after  Kohl- 
schiitter.) 

is  more  easily  induced  at  a  particular  hour.  No  one  of 
these  conditions  alone  will  induce  the  condition  or 
response,  but  all  together  usually  suffice.  Like  many 
another  reaction  it  is  favoured  by  suggestion  or  expecta- 
tion. If  one  fears  one  is  to  have  a  bad  night,  sleep  is 
usually  slow  in  coming;  while  if  one  expects  restful 
sleep,  it  comes  promptly. 


WORK,    FATIGUE,    AND    SLEEP  327 

What  the  reaction  is  that  causes  sleep  is  also  much  in 
dispute.  Changes  have  been  demonstrated  in  the  cir- 
culation. Blood  pressure  is  low  in  sleep  and  varies 
inversely  with  the  depth  of  sleep,  is  lowest  when  the 
depth  of  sleep  is  greatest.  The  blood-vessels  in  the  brain 
are  relaxed,  although  filled  with  blood,  and  constrict 
when  sleep  is  disturbed  or  during  dreams.  Respiration 
is  changed  in  characteristic  ways,  and  all  of  the  vital 
processes  have  their  activity  reduced.  Some  change 
certainly  occurs  in  the  nervous  system,  also,  but  what 
its  exact  character  is,  has  not  been  decided.  Evidence 
is  tending  toward  the  assumption  that  there  is  some 
loosening  of  the  connections  between  the  different  ele- 
ments, such  as  increased  resistance  at  the  synapses  to 
the  passage  of  excitations,  but  how  it  is  brought  about  is 
still  entirely  conjectural.  Certain  it  is  that  the  nervous 
system  is  less  easily  aroused  during  sleep  and  that  the 
course  of  action  is  less  controlled.  Nervous  action  is  not 
abolished,  however,  as  is  proved  by  the  presence  of  reflexes 
and  by  dreams.  Whether  this  reduced  activity  is  due  to 
the  changes  in  circulation  or  the  changes  in  circulation  are 
due  to  the  reduced  nervous  activity,  or  each  is  a  result 
of  some  common  cause,  cannot  be  decided  from  the  facts 
at  hand.  Whatever  sleep  may  be,  it  is  obvious  that  it  is 
a  state  that  conduces  to  the  restoration  of  the  tissues 
that  have  been  subjected  to  the  wear  and  tear  of  the  day. 
The  effects  of  fatigue  are  nullified.  The  cell  bodies  are 
restored  to  their  normal  condition,  the  waste  products 
are  eliminated  from  muscle  and  blood.  On  the  whole 
sleep  seems  to  be  an  instinctive  or  habitual  response  that 
comes  at  a  more  or  less  regular  time,  that  is  favoured 


328  ESSENTIALS   OF   PSYCHOLOGY 

by  a  mild  fatigue,  and  by  the  absence  of  external  dis- 
turbance. During  the  period  of  sleep  the  vital  pro- 
cesses are  reduced,  the  higher  nerve-centres  are  only 
slightly  active,  and  the  processes  of  repair  exceed  those 
of  wear. 

Dreams.  —  A  usual  accompaniment  of  sleep  is  the 
dream.  Dreams  are  excellent  evidence  of  the  reduced 
control  during  the  sleeping  condition.  They  can  be 
shown  to  be  often  excited  by  external  stimulation,  their 
content  is  usually  in  some  way  connected  with  the  events 
of  the  preceding  day.  The  course  of  the  dream  is  deter- 
mined by  the  laws  of  association.  These  run  their 
course  without  full  control,  and  the  results  are  not  subject 
to  the  same  censorship  as  in  the  waking  state.  We 
dream  events  that  would  not  be  permitted  to  make  their 
appearance  in  waking  life,  and  we  accept  results  as  true 
that  we  would  immediately  reject  if  awake,  and  that  are 
rejected  when  we  do  wake.  Both  this  lack  of  control 
and  increased  credulity  are  the  concomitants  of  the  dis- 
sociated character  of  the  nervous  system.  Parts  of  the 
cortex  only  are  awake,  and  those  parts  alone  determine 
the  course  of  thought  and  pass  upon  the  results  of  the 
thinking.  The  bizarre  nature  of  dreams  is  the  result 
of  this  lack  of  control.  Very  recently  Freud  has  elab- 
orated a  theory  that  dreams  are  the  expression  of  dom- 
inant ideas  that  are  repressed  during  the  waking  life. 
He  has  made  much  use  of  the  dream  in  determining  the 
character  of  these  fixed  ideas,  which  play  a  large  part 
in  the  causation  of  a  number  of  diseased  conditions. 
The  dream  content  he  regards  as  highly  symbolical  and 
representative  of  much  that  it  does  not  express.  The 


WORK,   FATIGUE,   AND   SLEEP  329 

details  of  the  theory  are  not  in  place  here,  but  emphasise 
the  statement  that  the  nature  of  dreams  is  due  to  the 
ordinary  association  processes,  with  little  of  the  control 
and  without  the  censorship  of  the  waking  life. 

REFERENCES 

MAX  OFFNER  :  Mental  Fatigue.  Tr.  by  Whipple. 

MYERS  :  Experimental  Psychology,  pp.  189-200. 

JUDD  :  Psychology,  ch.  xiv. 

JONES  :  Freud's  Theory  of  Dreams,  Am.  Jour,  of  Psy.,  1910,  p.  283. 


CHAPTER  XV 
THE  INTERRELATIONS   OF   MENTAL  FUNCTION 

Criticism  of  Faculty  Psychology.  —  For  the  sake  of 
convenience  we  have  been  treating  the  mental  operations 
separately  and  may  have  left  the  impression  that  each 
of  the  names  used  stands  for  a  separate  function  or  thing. 
This  was  in  some  degree  the  assumption  of  the  older 
psychologies  and  still  is  the  prevailing  popular  belief. 
One  speaks  of  attention  and  of  memory  and  of  other 
processes  because  they  represent  mental  capacities  which 
it  is.  desirable  to  discuss  together.  The  popular  mind 
always  finds  it  easy  to  make  a  substance  of  the  function 
and  to  speak  of  the  memory,  the  will,  and  so  on,  as  if 
they  were  separate  entities  or  forces.  In  the  very  early 
psychologies,  these  functions  were  personified  and  the 
older  men  were  inclined  to  speak  as  if  man  were  a  partner- 
ship in  which  each  partner  had  separate  abilities  and 
capacities,  and  as  if  these  capacities  were  practically 
independent  one  of  the  other.  In  the  discussions  of 
modern  psychology  there  is  no  such  implication.  The 
words  stand  for  nothing  but  observed  facts,  —  the  fact 
that  one  remembers,  that  one  acts  and  makes  decisions, 
or  that  one  attends.  What  may  be  behind  the  activity 
we  do  not  pretend  to  know,  but  we  certainly  do  not  care 
to  assert  that  anything  is  behind  any  act  or  activity. 
330 


THE    INTERRELATIONS   OF   MENTAL   FUNCTION      331 

The  Transfer  of  Training.  —  One  problem  of  consider- 
able practical  importance  is  the  degree  of  relation  and  the 
mutual  dependence  of  the  different  capacities.  In  con- 
nection with  training  it  is  interesting  to  know  if  one  may 
train  a  capacity  by  training  some  other  capacity,  or  how 
far  training  in  one  field  may  be  helpful  in  some  other. 
The  theoretical  considerations  may  give  any  conclusion 
indifferently,  and  popular  opinion  seems .  to  be  much 
divided  as  to  how  far  the  effects  of  training  may  spread 
from  the  function  actually  exercised  to  other  related 
functions.  There  is  also  equal  difference  of  opinion  as 
to  what  are  related  functions  and  how  they  may  be 
trained.  Two  opposing  general  principles  are  currently 
accepted  and  serve  as  a  basis  for  popular  opinion.  On 
the  one  hand,  the  separate  functions  have  been  regarded 
as  absolutely  distinct ;  on  the  other,  any  training  is 
assumed  to  be  effective  for  all  mental  capacities.  Ob- 
viously with  such  wide  diversity  in  general  theory,  there 
is  a  necessity  for  appeal  to  closer  analysis  and,  if  possible, 
to  actual  trial. 

The  Primary  Functions  of  Mind. — Our  earlier  analysis 
has  shown  that  the  different  functions  have  much  in 
common.  The  fact  that  impressions  are  retained  is  fun- 
damental, not  for  an  explanation  of  memory  only,  but 
for  the  control  of  attention  and  action  and  almost  every- 
thing else.  It  must  give  the  materials  of  reasoning 
as  well  as  much  of  the  control  of  the  reasoning  opera- 
tions. A  complete  analysis  shows  that  we  have  three 
simple  processes  that  are  fundamental  for  all  the 
cognitive  operations,  and  for  many  of  the  feeling  and 
active  processes.  These  are  the  facts  of  sensation,  of 


332  ESSENTIALS   OF   PSYCHOLOGY 

retention  and  recall,  and  of  selection  and  control.  These, 
together  with  the  complementary  processes  of  recognition, 
belief,  instinct,  and  feeling,  suffice  to  explain  all  the 
functions  of  consciousness.  Perception  depends  upon  the 
control  of  the  entering  sensation  plus  the  recall  of  related 
and  interpreting  elements  which,  in  their  turn,  are 
selected  to  harmonise  with  the  general  setting,  objective 
and  subjective.  For  example,  one  comes  into  a  furnished 
room  tired  and  accordingly  a  chair  catches  the  attention. 
This  perception  involves  a  rhomboid  of  colour  upon  the 
retina;  earlier  experiences  replace  the  rhomboid  with  a 
square  surface,  acute  and  obtuse  angles  by  right  angles, 
and  so  on.  We  have  a  combination  of  sensations  and 
memories,  controlled  by  the  needs  of  the  moment,  a 
process  we  call  perception.  Similarly  one  comes  into  a 
bare  room,  feels  tired,  and  the  sensations  with  the  general 
setting  call  out  the  memory  of  a  chair,  perhaps  of  the 
same  chair.  We  call  this  process  memory  or  imagina- 
tion according  as  the  recalled  chair  is  familiar  or  unfa- 
miliar. The  only  appreciable  difference  in  the  two  pro- 
cesses is  the  presence  in  perception  of  the  rhomboid  of 
colour  upon  the  retina.  Again  the  memory  of  the  chair 
may  start  a  train  of  movements  that  sends  one  into  the 
next  room  for  a  chair  or  to  the  telephone  to  order  one 
seen  in  a  shop  window  an  hour  before.  We  call  this  will, 
but  it  is  different  from  memory  only  in  that  the  associated 
movements  are  permitted  to  run  their  course,  again  under 
the  control  of  the  purpose  and  knowledge  of  one's  credit 
at  the  shop  and  the  permanence  of  the  need.  This  dif- 
ference is  even  less  when  one  considers  that  every  memory 
and  every  perception  tends  to  call  out  movements  of 


THE    INTERRELATIONS    OF   MENTAL   FUNCTION      333 

some  sort,  and  that  what  really  distinguishes  them  from 
will  is  the  degree  or  amount  of  the  movement,  not  its 
presence  or  absence.  In  memory  or  perception  the 
motor  discharge  ends  in  slight  movements,  while  in  will 
the  movements  are  an  important  part.  Any  of  the  other 
functions  that  are  ordinarily  distinct  may  be  regarded 
as  differently  compounded  out  of  the  same  elements. 
The  combinations  alone  are  different ;  the  elements  and 
the  conditions  that  control  the  selection  are  largely  the 
same  in  each.  It  is  to  be  expected  that  any  change  in 
any  function  will  affect  in  some  degree  each  of  the  other 
functions.  Either  it  will  supply  new  materials  that  may 
enter  into  other  functions,  or  will  change  the  conditions 
that  control  the  selection  and  arrangement  of  the  ma- 
terials. 

Names  of  Processes  are  of  Functions  not  Entities.  — 
Not  alone  are  the  different  functions  interrelated  as  dif- 
ferent expressions  or  combinations  of  the  same  mental 
materials  and  laws,  but  in  any  single  act  each  is  likely 
to  be  involved  in  some  degree.  One  turns  in  quick  suc- 
cession from  memory  to  action,  from  reasoning  to  imagi- 
nation, and  then  to  perception,  and  each  is  distinguish- 
able from  the  others  only  by  abstract  analysis.  The 
separate  functions  are  not  any  more  separated  really  than 
are  different  applications  or  uses  of  the  same  function. 
The  memory  employed  in  learning  nonsense  syllables 
is  more  different  from  that  used  in  learning  historical 
events  in  their  logical  succession  than  is  the  latter  from 
the  reasoning  employed  in  reconstructing  some  partly 
forgotten  event  on  the  basis  of  its  remembered  antece- 
dents. The  first  two  are  certainly  memory,  the  latter 


334  ESSENTIALS   OF   PSYCHOLOGY 

is  just  as  certainly  reason.  What  is  different  and  what 
marks  the  lines  of  division  in  consciousness  are  the  uses 
to  which  certain  processes  are  put.  These  processes 
receive  names  that  correspond  to  the  uses,  even  when 
the  elements  or  conditions  are  essentially  the  same. 
The  problem  of  how  far  training  may  spread  must  be 
attacked  by  experiment  and  observation ;  there  is 
nothing  in  the  nature  of  mental  capacities  that  gives 
certainty  that  training  may  not  spread  from  one  function 
to  another,  and  nothing  that  indicates  that  training  in 
one  field  has  any  particular  amount  of  influence  in  any 
other.  All  that  can  be  said  on  general  principles  is  that 
where  two  functions  have  something  in  common,  train- 
ing in  one  will  probably  have  an  effect  upon  the  other; 
where  there  is  nothing  in  common,  training  in  one  capac- 
ity will  be  without  influence  upon  the  other.  On  purely 
theoretical  grounds  one  would  expect  that  use  anywhere 
either  would  provide  new  materials  or  would  add  new 
elements  of  control  that  might  be  used  in  any  other  field. 
It  is  altogether  probable  that  the  effect  of  many  activities 
upon  other  capacities  may  be  negligible  in  amount,  and 
so  of  no  practical  importance.  All  that  can  be  said  with 
any  certainty  is  that  one  may  expect  any  training  what- 
ever to  spread  beyond  the  particular  function  exercised 
to  any  other  function  that  has  anything  in  common 
with  it.  The  problem  is  to  determine  what  functions 
have  enough  in  common  to  make  the  spread  from  one  to 
the  other  appreciable,  and  to  discover  means  of  measur- 
ing the  practice  and  its  effects  on  the  other  functions. 
Not  only  is  it  truejhat  two  functions  of  different  names 
have  much  in  common,  but  also  activities  that  ordinarily 


THE    INTERRELATIONS   OF   MENTAL  FUNCTION      335' 

are  grouped  under  the  same  name  need  not  be  sufficiently 
alike  to  make  training  in  one  have  any  influence  upon  the 
other.  For  example,  in  memory  it  has  long  been  a  ques- 
tion whether  training  in  learning  things  of  one  sort  in- 
creases the  capacity  for  learning  things  of  another.  The 
practical  problems  involved  are  twofold,  —  first,  how  far 
is  practice  in  a  function  effective  in  increasing  the 
capacity  for  exercising  the  same  function  on  other  ma- 
terial ;  and  second,  how  far  will  training  in  one  have 
an  effect  upon  other  functions  and  capacities. 

Can  Memory  be  Trained  ?  —  For  an  answer  to  our 
question  we  must  turn  to  an  examination  of  the  results 
of  experiments,  —  first  of  the  effects  of  training  one  func- 
tion upon  other  expressions  of  the  same  function,  and 
then  upon  the  transfer  of  training  from  one  function  to 
another.  The  field  that  has  been  best  developed  is 
memory.  It  has  long  been  a  question  whether  it  is 
possible  to  train  one's  capacity  to  remember  facts  of  one 
sort  by  practice  in  learning  some  other  set  of  facts.  The 
first  answer  to  this  question  in  more  recent  times  was  a 
decided  negative.  James  argued  that  in  learning  one 
statement  a  different  tract  in  the  cortex  must  be  involved 
from  that  involved  in  learning  any  other.  Consequently 
training  one  nerve  tract  would  have  no  more  effect 
upon  another  tract  than  would  practice  in  bending  a 
finger  upon  the  ability  to  walk.  James  also  put  the 
opinion  to  practical  proof  by  learning  a  bit  of  verse, 
then  spending  a  month  in  practice  on  other  poetry,  and 
testing  the  efficiency  acquired  by  learning  other  stanzas 
of  the  test  material.  He  found,  on  the  average,  that 
there  was  little  if  any  gain  after  the  long  training  and 
concluded  that  memory  cannot  be  trained. 


336  ESSENTIALS   OF   PSYCHOLOGY 

More  recent  tests  by  Ebert  and  Meumann  came  to  the 
opposite  conclusion.  They  worked  with  various  sorts 
of  sense  and  nonsense  material.  First,  the  untrained 
capacity  was  tested  for  one  sort  of  material ;  then  a 
long  period  was  devoted  to  learning  materials  of  another 
sort.  Then  the  first  sort  of  material  was  learned  again 
and  the  ease  of  learning  after  practice  was  compared 
with  the  original.  Other  practice  series  were  made  and 
again  tested.  The  results  showed  that  nonsense  syllables 
would  increase  the  ease  of  learning  philosophical  prose 
or  arbitrary  visual  signs  by  from  50  to  70  per  cent.  They 
conclude  that  learning  anywhere  will  increase  the  effi- 
ciency of  memory  everywhere,  that  practice  in  learning 
material  of  any  one  kind  will  have  a  marked  effect  in 
learning  any  other.  The  conclusion  has  been  criticised 
on  the  ground  that  the  test  series  for  each  sort  of  material 
were  so  long  that  there  was  considerable  opportunity 
for  training  in  them  and  that  a  large  part  of  the  training 
must  have  come  from  practice  in  the  tests,  not  through 
transfer  from  practice  on  other  sorts  of  material.  The 
experiments  have  been  repeated  by  Dearborn,  with  the 
precaution  of  taking  a  test  series  without  any  training, 
and  comparing  the  results  with  those  after  an  intervening 
period  of  training.  The  results  indicate  that  the  training 
has  some  effect  but  nothing  like  the  amount  that  Ebert 
and  Meumann  thought.  Probably  the  effect  of  training 
in  one  field  upon  learning  in  another  will  amount  to  from 
10  to  20  per  cent  as  compared  with  the  50  or  more  that 
Ebert  and  Meumann's  experiments  indicated. 

Training  Memory,  Training  Attention.  —  If  one  asks 
how  learning  one  thing  can  have  an  effect  upon  learning 


THE   INTERRELATIONS    OF   MENTAL   FUNCTION      337 

something  else  in  spite  of  the  fact  that  the  nervous 
structures  involved  must  be  different  in  each,  the  answer 
undoubtedly  is  to  be  found  in  the  fact  that  learning  of 
any  kind  involves  many  common  factors.  One  must 
always  attend  to  the  material  learned,  and  in  the  experi- 
ments in  question,  one  must  learn  to  attend  under  new 
and  unusual  conditions  and  to  materials  that  one  usually 
has  tried  to  neglect.  The  formation  of  habits  of  attend- 
ing in  general  and  of  attending  to  unusual  materials  and 
under  unusual  conditions  are  the  elements  that  serve  to 
facilitate  learning  under  the  different  circumstances  and 
that  may  be  transferred  to  learning  different  material 
under  the  same  circumstances.  In  the  learning  of  every- 
day life  still  other  common  factors  must  be  recognised. 
There  are  many  structural  elements  in  common  between 
things  and  even  sciences  that  are  called  by  different 
names.  The  same  fact  is  used  in  different  connections, 
and  the  resulting  compound  is  given  a  different  name  in 
each  connection.  For  example,  the  principles  of  history 
are  frequently  similar  to  the  laws  of  biology,  and  the 
spirit  and  attitude  are  very  similar  in  all  sciences.  All 
these  facts  and  principles  learned  in  one  field  save  time 
and  work  in  other  fields.  The  improvement  in  one  sort 
of  memory  acquired  by  training  some  other  does  not 
depend  upon  the  training  of  some  single  function  or 
thing,  but  is  due  to  the  fact  that  learning  anything 
develops  habits  of  attending  and  accustoms  one  to  learn 
new  materials  and  under  new  conditions.  What  is  trained 
is  some  common  function,  not  memory  in  general. 

Transfer  of  Training  in  Discrimination.  —  Very  much 
the  same  result  has  been  obtained  in  experiments  for 


338  ESSENTIALS  OF  PSYCHOLOGY 

training  discrimination.  It  has  been  shown  by  Coover 
and  Angell  that  discrimination  for  visual  stimuli  is  im- 
proved by  training  in  the  discrimination  of  sounds,  and 
the  quickness  of  response  in  one  way  to  one  sort  of  stim- 
ulus is  increased  by  training  in  another  form  of  re- 
sponse to  another  stimulus.  The  effects  of  the  training 
again  may  be  traced  to  the  improvement  in  some  capac- 
ity common  to  the  two  activities.  Training  in  the  con- 
trol of  movement  shows  the  same  transfer  from  one  field 
to  another  as  is  demonstrated  for  these  more  intellectual 
capacities  and  activities.  One  may  conclude  in  general 
that  exercise  of  one  sort  tends  ordinarily  to  improve- 
ment of  related  capacities.  This  rule  is  not  without 
exceptions,  for  training  may  make  learning  more  difficult 
under  other  circumstances  and  for  certain  sorts  of  activi- 
ties, even  if  they  bear  the  same  name.  An  instance  of 
this  was  cited  in  the  chapter  on  memory.  Common  ob- 
servation indicates  that  training  in  rote  memory  is  likely 
to  interfere  with  skill  in  remembering  ideas,  in  logical 
memory ;  and  vice  versa,  skill  in  remembering  ideas  may 
make  one  neglect  the  words  and  so  learn  them  less  easily 
than  would  the  untrained  individual.  The  explanation 
reduces  to  the  same  law  as  before.  What  is  trained  is 
a  habit  of  attending,  and  attending  in  one  way  tends  to 
prevent  attending  in  opposed  ways.  Whether  training 
is  harmful  or  beneficial  depends  upon  whether  some  habit 
is  common  to  the  two  processes  under  discussion,  or 
whether  a  habit  established  in  one  operation  will  be  in- 
jurious in  the  other.  One  can  assert  at  present  only  that 
whether  training  in  one  act  or  in  one  field  will  be  bene- 
ficial to  other  different  acts  or  functions  of  the  same  sort 


THE   INTERRELATIONS   OF   MENTAL  FUNCTION      339 

depends  upon  whether  the  two  functions  have  anything 
in  common,  and  whether  the  common  factor  works  in  the 
same  way  in  each  of  the  activities  in  question. 

Training  of  General  Intelligence.  —  Still  more  com- 
plicated is  the  problem  and  less  definite  the  result,  when 
one  turns  from  different  expressions  of  the  same  sort  to 
the  question  whether  there  is  anything  .in  common  be- 
tween functions  or  capacities  not  of  the  same  general 
kind.  The  results  of  one  of  the  best-known  theories 
assert  that  a  definite  relation  does  exist  between  skill 
in  one  field  and  the  general  intelligence  of  the  subject. 
It  is  insisted  that  all  capacities  are  sufficiently  inter- 
related to  have  skill  in  one  involve  skill  in  any  other. 
Two  comprehensive  sets  of  experiments  have  been  carried 
through  in  connection  with  the  problem,  but  unfortu- 
nately the  results  are  directly  opposed.  Spearman  found 
that  accuracy  in  discrimination  of  any  sort  is  closely 
related  to  the  general  ability,  as  shown  by  class  stand- 
ing and  the  estimation  of  teachers  and  fellow-students. 
Thorndike,  however,  by  like  methods,  finds  a  very  slight 
similarity  between  general  intelligence  and  sense  dis- 
crimination. With  these  opposed  results,  one  can  draw 
no  definite  conclusion  concerning  the  degree  in  which 
the  different  capacities  are  related.  Consequently  one 
can  say  nothing  about  how  far  training  may  extend 
from  one  capacity  to  another.  It  can  only  be  asserted 
that  it  is  possible  that  training  will  have  some  effect  in 
other  capacities  that  have  common  factors,  but  whether 
much  or  little  can  be  determined  only  by  experiment, 
and  satisfactory  experiments  are  as  yet  lacking. 

Training  from  Subjects  of  School  Curriculum.  —  Still 


340  ESSENTIALS   OF   PSYCHOLOGY 

farther  are  we  from  being  able  to  assert  that  certain  sub- 
jects in  the  school  curriculum  will  have  an  effect  upon 
any  particular  capacity, 'or  that  one  subject  will  have 
a  greater  effect  than  any  other.  It  is  frequently  asserted 
that  mathematics  trains  reasoning,  classics,  memory, 
and  so  on.  These  assertions  are  based  altogether  on 
assumption  and  apparently  assume  an  out-of-date 
psychology.  Certainly  few  experiments  have  been  per- 
formed and  no  tests  of  the  effects  of  studying  one  subject 
apart  from  others  have  extended  over  a  sufficiently  long 
time  to  get  trustworthy  results.  From  general  con- 
siderations it  is  evident  that  the  results  of  studying  any 
subject  will  depend  in  very  large  degree  upon  how  it  is 
studied  and  how  it  is  taught.  Mathematics  may  be  made 
a  mere  exercise  in  memory,  while  history  or  the  classics 
when  studied  by  some  methods  may  be  primarily  training 
in  reasoning.  The  most  that  may  be  said  with  certainty 
is  that  the  sort  of  training  derived  from  any  subject  will 
depend  more  upon  the  way  it  is  taught  than  upon  the 
subject.  Any  subject  may  give  any  sort  of  training, 
and  probably  every  sort  of  training  in  some  degree,  but 
how  much  depends  upon  circumstances  that  cannot  be 
determined  from  the  name  of  the  subject.  At  present 
it  is  not  possible  to  say  how  far  any  activity  may  be  pre- 
pared for  by  any  subject. 

Summary.  —  The  outcome  of  the  discussion  of  how 
far  doing  one  thing  is  a  training  for  something  else  has 
been  very  unsatisfactory.  Training  gained  by  doing 
any  one  thing  will  be  general,  and  will  aid  in  doing  any- 
thing else  in  the  same  field.  How  much  it  will  aid,  or 
whether  it  will  aid  at  all,  depends  upon  how  much  there 


THE   INTERRELATIONS   OP   MENTAL   FUNCTION      341 

is  in  common  between  the  two  operations,  and  this  can 
be  determined  only  by  experiment.  Very  much  the  same 
answer  must  be  given  to  the  question  how  far  exercise 
of  one  function  has  an  effect  upon  others.  There  may 
be  some  effect  or  there  may  be  none,  according  to  the 
relation  of  the  two  functions.  There  is  little  evidence  of 
any  single  function  or  faculty,  like  general  intelligence, 
that  may  be  developed  by  all  sorts  of  training  and  be 
applicable  in  all  fields.  The  most  that  can  be  said  posi- 
tively is  that  one  may  best  prepare  one's  self  to  do  any- 
thing by  doing  that  thing.  It  does  not  follow  that  doing 
that  thing  will  be  the  best  preparation  for  life,  or  for 
success  in  that  particular  capacity,  but  certainly  skill  in 
that  function  can  be  most  surely  acquired  by  practising 
it  directly.  A  general  training  is  indispensable,  not 
because  it  gives  command  of  a  particular  trade  or  pro- 
fession, but  because  anything  can  be  understood  fully 
only  in  terms  of  other  things,  and  because  highest  success 
is  possible  only  when  preparation  has  been,  not  for  one 
task  alone,  but  for  many  tasks  of  a  related  kind,  —  for 
all  in  fact  that  have  any  bearing  upon  the  chosen  career. 
The  main  outcome  is  to  enforce  conservatism  in  assert- 
ing just  how  best  to  obtain  a  general  training.  The  one 
assured  result  is  that  training  for  any  particular  task  or 
operation  can  be  acquired  by  doing  that  particular  thing. 
If  the  discussion  has  served  to  emphasise  the  fact 
that,  on  the  one  hand,  mind  is  not  a  collection  of  unre- 
lated faculties  and,  on  the  other,  that  it  is  not  a  single 
force  or  faculty,  but  rather  that  mind  is  merely  a  term 
applied  to  a  number  of  different  functions  spoken  of 
collectively,  the  time  will  have  been  well  spent.  When 


342  ESSENTIALS    OF   PSYCHOLOGY 

certain  of  these  separate  functions  are  grouped  in  one 
way  or  to  the  accomplishment  of  one  end,  the  process  is 
perception ;  when  grouped  in  another  way,  imagination , 
in  a  third,  memory ;  and  in  a  fourth,  reasoning.  When 
other  functions  are  introduced  and  practical  activities 
are  controlled,  the  process  is  will.  Other  modifications 
constitute  the  emotional  and  affective  processes.  In  any 
event,  what  gives  the  name  to  the  function  in  everyday 
life  and  in  scientific  usage  are  not  the  materials  of  which 
the  mental  state  is  composed  or  even  the  laws  that  are 
revealed  in  the  operation,  but  the  end  that  the  function 
subserves.  The  fundamental  laws  of  operation  and  the 
simple  elements  are  relatively  few  as  compared  with 
the  ends  they  subserve  and  the  names  for  functions  or 
'  faculties,'  either  popular  or  scientific.  The  division  of 
the  treatment  of  psychology  into  chapters  devoted  to 
these  particular  functions  is  for  convenience.  The  func- 
tions themselves  are  not  distinct. 

REFERENCES 

ANGELL,  PILLSBURY,  JUDD  :  Formal  Discipline     Educational  Re- 
view, June,  1908,  p.  31. 
ROYCE  :  Outlines  of  Psychology,  pp.  54-56 
W.  H.  HECK  :  Mental  Discipline. 
COLVIN  :  The  Learning  Process. 


CHAPTER  XVI 
THE   SELF 

THE  last  problem,  the  nature  of  the  self,  the  'I/  is 
fundamental.  Throughout  the  book,  we  have  been  ask- 
ing what  man  can  do  and  what  his  mental  processes  are 
and  what  they  mean.  Now  we  must  raise  the  more  gen- 
eral question,  what  is  it  that  makes  the  self,  and  how  is 
the  self  known  ?  Much  of  the  discussion  of  the  nature  of 
the  self  in  philosophy  and  in  popular  thought  and  dis- 
cussion has  little  to  do  with  psychology.  On  many  of 
these  problems  the  opinion  of  the  psychologist  is  little  if 
any  more  valuable  than  that  of  the  untrained  layman. 
Certain  phases  of  the  problem  of  the  self  are  of  a  psy- 
chological character,  however,  and  their  consideration  is 
not  only  important  for  itself,  but  serves  to  give  a  review 
in  perspective  of  many  of  the  more  concrete  discussions. 
Without  prejudice  to  the  problems  that  lie  beyond  the 
range  of  psychology,  we  speak  from  the  standpoint  of  the 
psychologist. 

The  Content  of  the  Idea  of  the  Self.  —  The  self  may  be 
approached  from  two  distinct  sides.  One  may  ask  what 
is  in  mind  when  one  thinks  '  I.'  This  question  is  on  the 
same  level  as  any  other  concerning  the  nature  of  a  mental 
state;  it  is  a  question  of  structure.  The  other  set  of 
questions  deal  with  the  capabilities  of  the  man;  they 
ask  what  the  self  does  in  different  relations,  they  raise 

343 


344  ESSENTIALS    OF    PSYCHOLOGY 

problems  of  function.  The  one  problem  is  of  what  the 
man  himself  appreciates  as  himself ;  the  other  asks  what 
it  is  that  makes  an  observer  regard  the  man  as  con- 
tinuously the  same  person,  why  he  is  trusted  to  act  in  a 
definite  way,  at  all  times.  The  problems  are  different, 
although  closely  related.  What  one  accomplishes  colours 
one's  idea  as  to  what  one  is,  and,  conversely,  what  one 
thinks  one's  self  to  be  has  a  considerable  effect  in  deter- 
mining what  one  can  accomplish.  For  our  purposes,  one 
is  the  problem  of  the  self  as  viewed  from  within,  the  other 
the  problem  of  the  self  as  it  presents  itself  to  the  onlooker. 
The  idea  that  is  in  consciousness  when  one  thinks  '  I ' 
varies  from  moment  to  moment  and  from  individual  to 
individual.  It  has  been  suggested  that  it  is  made  up  in 
part  of  the  mirror  images  of  one's  self,  in  part  of  the  frame- 
work of  nose  and  eyebrows  through  which  one  views  the 
world,  and  of  the  constant  background  of  tactual  and 
organic  sensations.  Probably  some  of  these  elements 
may  be  present  in  the  idea  of  the  self,  and  each  has,  at 
some  time  or  other,  helped  to  make  the  individual  ac- 
quainted with  himself.  The  most  prominent  group  of 
elements  in  the  total  picture  is  the  mass  of  organic  sensa- 
tions. They  are  always  present,  although  they  vary  in 
quality,  and  probably  always  colour  the  mental  life. 
When  '  I '  feel  ill,  they  are  of  one  sort ;  when  '  I '  feel 
well,  they  are  of  another  character.  In  either  case,  ill- 
being  or  well-being  is  appreciated  through  them.  The 
importance  of  these  organic  sensations  has  been  em- 
phasised by  the  fact  that  in  certain  cases,  loss  of  appre- 
ciation of  self -identity  seems  to  depend  upon  a  trans- 
formation of  the  organic  sensations.  The  individual 


THE   SELF 


345 


whose  permanent  sensations  have  undergone  a  change, 
no  longer  feels  himself.  It  seems  likely  when  a  patient 
in  delirium  seems  to  be  watching  himself  from  above  or 
from  somewhere  else  outside  of  his  body,  that  the  disease 
processes  have  changed  these  sensations,  and  the  man  no 
longer  recognises  himself.  These  sensations  constitute 
only  a  part  of  the  idea  of  the  self  regarded  as  content. 
One  must  add  the  social  elements  in  the  idea  that  are 
probably  even  more  important.  It  is  not  so  much  how 
one  actually  does  appear,  as  how  one  thinks  one  appears 
to  others  that  constitutes  the  notion  of  the  self.  In  this 
idea,  as  James  points  out,  a  large  place  is  taken  by  ex- 
ternal belongings,  clothing,  automobiles,  bank  account, 
and  possessions  of  all  sorts.  One  grows  with  one's  goods, 
and  even  with  one's  friends  and  the  circle  of  acquaintances. 
But  while  all  of  these  elements  serve  to  give  tone  to  the 
idea  of  the  self,  that  idea  itself  is  a  concept  that  has  been 
developed  through  the  experience  of  the  individual  to 
represent  and,  in  part,  to  account  for  himself.  Like  all 
concepts,  the  content  may  vary  greatly;  but  the  thing 
represented  is  more  fixed,  although  that,  too,  is  subject 
to  constant  change  with  growth  and  with  the  phases  of 
experience  that  it  represents. 

The  Active  Self.  —  The  treatment  of  the  active  self 
offers  more  difficulties.  The  idea  of  the  self  as  an  agent 
has  developed  to  explain  the  unity  and  continuity  of 
conscious  processes  in  any  individual,  and  to  make  the 
consistency  of  the  different  acts  of  the  same  man  conceiv- 
able. If  consciousness  were  merely  a  mass  of  states,  an 
individual's  experience  would  not  be  regarded  as  con- 
tinuous, as  parts  of  a  single  whole,  but  would  be  just  a 


346  ESSENTIALS    OF   PSYCHOLOGY 

jumble  of  separate  events  or  things.  Even  the  mental 
states  of  any  moment  would  be  merely  separate  states, 
it  has  been  asserted,  unless  they  were  held  together  in 
some  way.  The  concept  of  the  self  has  been  developed 
popularly  and  philosophically  to  make  conceivable  the 
fact  that  mental  states  do  constitute  a  unity  and  that  all 
states  of  whatever  period  are  regarded  as  my  states. 
The  facts  that  are  implied  by  the  term  self  are  that  the 
different  experiences  are  parts  of  a  single  whole  which 
persists  from  life  to  death,  and  that  the  thoughts  of  any 
moment  constitute  a  unity.  More  practical  is  the  prob- 
lem, as  it  presents  itself  to  the  friend  or  business  associate. 
This  is,  why  does  the  same  man  act  in  approximately  the 
same  way  toward  the  same  situations,  and  why  are  his 
methods  of  action  peculiar  to  himself?  When  a  man 
makes  a  sudden  change  in  his  course  of  action,  it  is  at 
once  said  that  he  is  no  longer  himself.  The  facts  that  are 
to  be  explained  in  connection  with  the  self  are  first,  the 
continuity  of  conscious  states ;  second,  the  unity  of  con- 
sciousness at  any  moment ;  and  third,  the  self -consistency 
of  action. 

The  Self  as  Accumulated  Habits.  —  One  of  the  most 
superficial  explanations  of  the  consistency  of  action  from 
moment  to  moment  is  to  be  found  in  the  persistence  of 
habitual  responses.  In  considerable  degree,  it  is  possible 
to  read  character  from  the  face.  So  far  as  this  is  possible 
at  all,  it  is,  as  was  said  in  an  earlier  chapter,  because  the 
face  retains  the  imprint  of  the  earlier  expressions  of  emo- 
tions and  of  feelings.  Every  thought  and  feeling  induces 
some  contraction  of  the  facial  muscles,  and  each  of  these 
contractions  leaves  its  impress  on  the  face  by  enlarging 


THE    SELF 


347 


the  muscle  or  by  wrinkling  the  skin.  Thus  old  expressions 
and  indirectly  old  experiences  write  their  record  on  the 
face  for  him  who  runs  to  read.  But  these  same  experiences 
induce  habits,  not  merely  in  the  facial  muscles,  but  in  all 
parts  of  the  psycho-physical  organism ;  in  consequence, 
even  the  most  general  mental  and  physical  responses 
and  attitudes  correspond  to  the  configuration  of  the  face. 
Both  have  been  developed  in  the  same  way.  In  truth, 
very  many  of  the  subtle  peculiarities,  which  together  con- 
stitute character,  are  traceable  to  habits.  Much  of  good 
temper  or  bad  temper  is  dependent  upon  the  habit  of 
smiling  or  of  scowling,  upon  the  habit  of  sharp  speech  or 
of  mild  speech.  Whether  the  first  and  natural  attitude 
toward  a  situation  is  of  pleased  acquiescence  or  of  fault- 
finding is  very  largely  a  matter  of  habit.  Even  the  moral 
elements  of  character  have  their  habitual  constituents. 
One  has  habits  of  honesty  and  punctuality  in  meeting 
obligations,  just  as  one  has  habits  of  rising  or  of  eating. 
It  is  as  difficult  to  break  a  habit  of  paying  bills  at  the 
end  of  the  month  as  a  habit  of  late  rising.  Bad  habits 
in  matters  of  right  action  may  reach  the  point  where  they 
are  as  difficult  to  break  as  a  drug  habit,  where  all  the  con- 
sequences of  the  acts  are  neglected.  At  this  stage,  the 
man  has  become  an  habitual  criminal,  and  self-restraint 
must  give  way  to  restraint  by  others.  A  self  of  one  sort 
may  become  altogether  changed  in  the  course  of  a  few 
years,  merely  through  the  development  of  a  new  set  of 
habits.  The  self  from  this  simple  point  of  view  is  in 
great  part  merely  the  accumulation  of  habits,  the  out- 
come of  the  earlier  actions  of  the  individual. 

The  Self  as  an  Expression  of  Organised  Experience.  — 


34§  ESSENTIALS    OF   PSYCHOLOGY 

Still  more  intimately  connected  with  the  development 
of  the  self  and  self-control  is  the  effect  of  earlier  experi- 
ences as  they  are  expressed  in  present  experience. 
Throughout  our  treatment  of  the  earlier  topics,  particu- 
larly in  connection  with  reasoning  and  action,  we  have 
had  occasion  to  emphasise  the  importance  of  the  system 
of  knowledge  and  the  system  of  purposes.  It  has  been 
pointed  out  that  attention,  perception,  memory,  and 
action  in  all  of  its  higher  forms  are  controlled  by  earlier 
experiences,  not  as  single  and  sporadic  elements,  but  as 
organised  systems.  Practically  all  of  the  important 
functions  that  are  ascribed  to  the  self  are,  when  ex- 
amined critically,  seen  to  be  due  to  the  action  of  earlier 
experience.  What  makes  one  man  different  from  any 
other  is  that  he  sees  differently,  thinks  differently,  and 
acts  differently.  These  depend  upon  the  actual  knowl- 
edge that  he  has  accumulated,  upon  the  associations  and 
habits  that  he  has  developed,  but,  above  and  beyond  that, 
upon  the  control  of  organised  knowledge  and  upon  de- 
veloped purposes.  The  individual  starts  life  with  cer- 
tain instincts  that  are  a  part  of  the  common  racial  in- 
heritance. The  early  self,  so  far  as  one  may  speak  of 
the  infant  as  having  a  self,  is  dependent  upon  these  in- 
stincts for  its  character.  As  he  grows,  these  are  first 
modified  by  experience,  then  experiences  become  the 
dominating  factors  in  determining  the  nature  of  the  re- 
sponses, mental  and  physical.  There  is  seldom  a  com- 
plete and  sudden  change  in  the  character.  It  is  only 
gradually  that  the  original  instinctive  character  is  modi- 
fied by  experience;  the  single  experiences  in  the  later 
stages  work  but  a  comparatively  slight  change.  The 


THE    SELF 


349 


original  kernel  of  the  self  constantly  grows  and  expands 
by  taking  up  into  itself  new  bits  of  knowledge.  As 
Tennyson  sings  in  his  'Ulysses/  '  I  am  a  part  of  all  that 
I  have  seen.'  Ordinarily  it  takes  years  to  make  a  marked 
difference.  The  self  of  to-day  is  not  noticeably  different 
from  the  self  of  yesterday,  although  it  is  markedly  dif- 
ferent from  the  self  of  twenty  years  ago.  Occasionally 
one  will  see  a  sudden  '  about-face  '  in  a  character.  In- 
stances of  sudden  conversion  may  be  cited.  Some  strik- 
ing event  seems  to  throw  new  light  on  the  relation  of  the 
individual  to  the  world  and  his  fellows,  and  his  entire 
attitude  changes,  and  with  that  his  actions.  Sometimes 
a  sudden  misfortune  will  destroy  the  confidence  built  up 
through  a  lifetime  of  successful  activity.  The  resolute, 
self-reliant  man  of  affairs  becomes  hesitant,  dependent, 
and  all  initiative  is  lost ;  he  becomes  a  human  derelict 
who  cannot  be  relied  upon  for  even  the  simplest  tasks. 
Such  sudden  changes  are  the  exception;  usually  char- 
acter is  of  slow  growth  and  the  changes  can  be  detected 
only  after  the  lapse  of  years.  The  individual  peculiari- 
ties and  the  consistency  of  action  that  mark  the  self 
depend  in  part  upon  the  habits  that  the  individual  de- 
velops, and  in  part  upon  the  control  exerted  by  the  ac- 
cumulated experiences  and  purposes  upon  thought  and 
action. 

The  Self  as  a  Continuous  Existence.  —  The  second 
function  or  characteristic  of  the  self,  the  fact  that  all 
mental  states  are  regarded  as  belonging  together,  de- 
pends in  part  at  least  upon  the  continuity  of  memory. 
Professor  James  has  asserted  that  what  makes  the  self 
continuous  is  primarily  the  fact  that  one  mental  state 


35°  ESSENTIALS    OF   PSYCHOLOGY 

always  laps  over  upon  the  next.  There  are  no  blank 
spaces  that  separate  one  moment  from  the  next.  At 
any  moment,  several  ideas  are  represented  at  different 
stages  of  development  or  disappearance.  Other  factors 
are  found  in  the  persistence  of  memories,  and  the  facts  of 
recognition.  The  self  probably  is  recognised  hi  very 
much  the  same  way  as  any  object.  The  older  experiences 
are  present  to  interpret  the  new ;  and  the  fact  of  recogni- 
tion of  objects,  as  well  as  the  recognition  of  the  self, 
serves  to  prove  the  continuous  identity  of  the  train  of 
experiences.  To  these  must  be  added  the  fact  of  the 
return  of  old  memories,  and  the  anticipation  of  future 
events  in  the  light  of  the  past.  When  these  anticipations 
are  confirmed  by  actual  experiences,  the  new  is  more 
firmly  bound  to  the  old  and  the  old  to  the  new.  That 
one  is  constantly  looking  forward  and  backward  from 
the  present  and,  particularly,  that  the  past  anticipations 
are  confirmed  by  the  events  of  the  present,  serve  to  bind 
past,  present,  and  future  into  a  single  whole.  The  con- 
tinuity of  reference,  the  development  of  types  and  mean- 
ings, and  the  confirmation  or  partial  modification  of  the 
meaning  of  one  time  by  the  meaning  of  the  next,  all  con- 
tribute their  share  to  establishing  the  continuity  of  the 
self,  as  well  as  of  the  thoughts  or  objects  themselves. 

The  Self  as  the  Unity  of  Experience.  —  To  say  that  the 
self  of  any  moment  is  a  unit  means  merely  that  the  com- 
ponent elements,  in  addition  to  being  controlled  and  sub- 
ordinated to  the  whole,  must  all  be  connected,  and  each 
must  add  its  share  to  the  whole.  As  was  said  in  the 
second  chapter,  the  consciousness  of  any  moment  cor- 
responds to  the  action  of  many  different  nerve  units  in 


THE   SELF  351 

many  different  parts  of  the  cortex,  but  to  be  conscious, 
any  one  of  these  elements  must  be  connected  with  all  of 
the  others  that  are  active  at  the  time.  To  be  conscious 
and  to  belong  to  the  unity  of  the  self  are  synonymous. 
This  mass  of  mental  states  not  only  belong  together, 
but  act  as  a  unit  in  the  control  of  all  subordinate  mental 
activities.  No  experience  is  ever  of  discrete  units,  nor 
is  any  single  process  alone  effective  in  determining  the 
course  of  mental  or  physical  activity.  This  intercon- 
nection, at  once  passive  and  active,  is  the  basis  of  the 
unity  of  the  self  at  any  moment.  One  often  speaks  of 
the  unconscious  or  the  subconscious,  as  if  there  were  a  con- 
sciousness detached  from  the  main  or  dominant  con- 
sciousness, separated  from  the  unity  that  has  just  been 
mentioned.  It  is  true  that  movements  are  often  made 
without  consciousness,  and  still  seem  to  be  controlled  by 
purposes.  There  are  other  instances  in  which  all  or  part 
of  a  course  of  thought  shows  characteristics  of  purpose 
that  might  have  been  developed  by  conscious  states,  but 
in  which  there  is  no  evidence  of  consciousness.  In  all  of 
these  cases  it  is  probably  safer  to  assume  that  the  deter- 
minants are  physiological  or  nervous,  rather  than  con- 
scious. Surely  the  only  safe  evidence  of  consciousness  is 
consciousness  itself.  An  unconscious  conscious  state  is 
a  contradiction  in  terms. 

Dissociated  Selves.  —  The  consistency  of  thought  and 
act  that  marks  the  man  as  peculiarly  himself,  the  persist- 
ence of  self-appreciation  from  day  to  day,  and  the  mo- 
mentary unity  of  experience,  all  go  back  for  their  explana- 
tion to  the  fact  that  all  the  accumulated  experiences  of 
the  individual  are  combined  into  a  single  whole  through 


352          ESSENTIALS  OF  PSYCHOLOGY 

the  manifold  interconnections  of  the  parts.  These  inter- 
connections give  meaning  to  the  different  parts,  and 
serve  to  direct  and  coordinate  the  various  activities. 
That  these  relations  and  factors  are  actual,  not  hypo- 
thetical, is  demonstrated  by  the  numerous  cases  of  dis- 
sociation of  the  self,  in  which  the  continuity  of  thought 
and  action  is  broken.  An  individual  who  is  dominated 
at  certain  times  by  one  set  of  purposes  and  ideals  will,  at 
other  times,  be  dominated  by  other  purposes  and  ideals. 
At  the  instant  of  change,  there  will  also  be  a  break  in  the 
continuity  of  memory,  and  in  the  degree  to  which  the 
selves  recognise  conventional  and  moral  restraints.  The 
individual  will  carry  on  the  ordinary  routine  life  until  some 
emotional  shock  or  injury  is  suffered.  Then  all  memory 
of  the  past  will  be  lost;  he  will  start  up  with  no  remem- 
brance of  his  surroundings ;  in  some  cases,  with  no  ap- 
preciation of  any  of  the  things  about,  and  none  of  his 
accumulated  knowledge.  In  many  cases,  the  selves  will 
alternate  for  a  considerable  time.  One  self  with  its 
peculiar  memories  and  characteristic  actions  and  feelings 
will  be  in  charge  for  a  time,  and  the  individual  will  have 
one  set  of  memories,  one  emotional  attitude  to  the  world ; 
then  suddenly  the  other  will  get  the  upper  hand,  all 
memories  acquired  by  the  earlier  self  will  be  forgotten, 
and  the  entire  character  of  the  individual  will  change. 
One  of  the  earlier  cases  reported  was  a  woman,  Felida  X, 
who  in  the  one  self  was  moody  and  bad  tempered ;  when 
the  other  self  came,  she  would  be  cheerful,  a  more  capable 
worker,  and  different  in  every  respect  from  the  first. 
These  states  alternated  for  a  period  of  thirty  years  or 
more.  They  would  be  separated  by  a  period  of  uncon- 


THE   SELF 


353 


sciousness  at  times,  and  at  times  the  change  from  one  to 
the  other  would  be  sudden  and  with  but  slight  warning. 
After  the  change,  the  immediately  preceding  events 
would  not  be  remembered.  Later,  when  Felida  had 
come  to  know  the  symptoms  of  the  change,  she  would 
write  down  the  things  she  would  need  to  know  in 
the  approaching  state.  She  was  a  small  shopkeeper, 
and  if -she  felt  the  change  coming  in  the  midst  of  a 
sale,  she  would  record  the  amount  of  the  purchase  or 
of  the  money  that  she  had  received  that  she  might 
continue  the  transaction  without  mistake  when  the  new 
self  appeared. 

So  far  as  present  knowledge  extends,  it  seems  that  the 
cause  of  the  dissociation  of  the  self  is  to  be  found  in  a 
disturbance  of  the  connections  between  the  experiences. 
The  emotional  shock  breaks  the  associations  between 
groups  of  cells,  or  cells  that  correspond  to  groups  of 
memories.  After  the  shock,  an  event  in  one  group  will 
recall  other  members  of  that  group  alone ;  the  recall  will 
not  extend  to  the  memories  dependent  upon  the  other 
group.  Also  and  more  important  for  the  explanation  of 
the  active  self,  the  acts  and  thoughts  and  emotions  will 
be  controlled  at  any  moment  by  the  experiences  that 
belong  to  one  group ;  elements  from  the  other  group  will 
have  no  effect  upon  action  at  the  times  the  other  group 
is  dominant.  The  acts  of  the  one  self,  or  group  of  ex- 
periences, will  be  consistent,  but  the  acts  of  one  self  will 
not  be  consistent  with  the  acts  of  the  other  self,  or  group 
of  experiences.  That  the  qualities  ordinarily  attributed 
to  the  self  disappear  or  are  greatly  modified  when  the 
connections  between  different  experiences  are  broken, 


354          ESSENTIALS  OF  PSYCHOLOGY 

is  strong  proof  that  the  self  in  the  normal  individual  is 
largely  determined  in  its  character  by  the  way  the  differ- 
ent experiences  interact.  This  series  of  connections  gives 
continuous  memory,  makes  the  experiences  of  any  mo- 
ment a  unit,  and  through  directing  thought  and  act  keeps 
the  self  of  one  moment  consistent  with  the  self  of  other 
moments. 

Slighter  signs  of  alternating  selves  may  be-  found 
in  normal  individuals.  The  hypnotic  condition  differs 
from  the  normal  very  much  as  one  of  the  dissociated 
selves  differs  from  another ;  and  selves  may  be  in- 
duced in  the  hypnotic  state  that  are  related  in  every 
practical  respect,  as  are  the  dissociated  or  alternating 
selves.  In  the  normal  state  there  are  seldom  memories 
of  the  hypnotic  state,  and  by  suggestion  during  hypno- 
tism it  is  easy  to  change  the  character  of  the  self,  practi- 
cally at  will.  Similar  normal  divisions  in  the  self  may 
be  seen  in  the  life  of  any  individual.  The  ordinary 
business  man  is  one  man  at  home,  and  another  in  his 
place  of  business.  He  thinks  differently,  and  acts  dif- 
ferently. Of  course  here  the  dissociation  is  restricted  to 
the  control  of  action;  memory  is  continuous,  and  the 
actions  are  not  sufficiently  different  to  prevent  the  man 
from  being  recognised  always  as  himself.  It  is  very 
interesting  to  note  that  various  groups  of  responses  are 
aroused  on  relatively  slight  suggestions.  Frequently 
men  undergo  changes  as  they  change  their  surroundings. 
A  man  may  be  perfectly  at  his  ease  in  his  own  home,  and 
very  much  embarrassed  or  very  diffident  when  in  a 
strange  place.  Clothing  frequently  plays  a  considerable 
part  in  suggesting  selves  or  groups  of  responses.  All  one's 


THE   SELF 


355 


self-possession  may  be  destroyed  if  one  finds  one's  self  in 
company  without  some  usual  article  of  apparel,  a  cravat, 
for  example.  Manners  frequently  are  put  on  with  the 
garments.  It  is  said  of  Stanley,  the  African  explorer, 
that  his  ability  to  make  a  speech  depended  upon  his 
wearing  a  small  cap  that  had  been  given  him  by  Living- 
stone. When  called  upon  to  reply  to  a  toast,  or  when  lec- 
turing, he  invariably  donned  this  cap.  Without  it,  he 
seemed  tongue-tied.  Many  lecturers  feel  lost  without 
a  reading  desk  even  if  they  never  use  notes,  and  the  ab- 
sence of  some  familiar  article  of  furniture  may  destroy 
their  composure.  In  each  of  these  cases,  the  familiar 
situation  or  the  familiar  article  arouses  a  group  of  ex- 
periences that  will  not  be  aroused  without  it.  The  ac- 
tions grow  out  of  the  experiences.  When  all  of  the 
usual  accompaniments  are  present,  the  course  of  thought 
and  speech  or  act  runs  smoothly;  without  some  appar- 
ently insignificant  element,  the  whole  complex  is  dis- 
turbed. 

The  Self  a  Social  Product.  —  One  appreciates  the 
character  of  the  effective  self  altogether  through  the 
social  relations.  Were  it  possible  for  a  child  to  grow  up 
alone,  he  would  have  no  appreciation  of  his  character. 
He  would  not  know  whether  he  were  quick  tempered 
or  slow  to  anger,  whether  he  were  honest  or  dishonest, 
strong  or  weak.  The  questions  that  grow  out  of  the  self 
problem  would  not  occur  to  him.  All  of  these  character- 
istics of  the  self  are  appreciated  only  when  there  is  a  chance 
to  compare  himself  with  others.  He  knows  himself  only 
as  he  sees  himself  reflected  in  the  opinions  of  others. 
This  statement  is  the  converse  of  the  other  statement, 


356  ESSENTIALS   OF   PSYCHOLOGY 

that  man  knows  others  or  at 'least  the  mental  processes 
of  others  only  in  so  far  as  he  can  interpret  their  acts  in 
terms  of  his  own .  conscious  states.  The  processes  of 
knowing  one's  self  and  of  knowing  others  are  correlative. 
Each  can  be  known  and  appreciated  only  in  the  light 
of  the  other.  One  passes  judgment  on  the  acts  of 
others  and  then  compares  his  own  acts  with  them,  to 
obtain  the  judgment  of  himself  and  others  upon  himself. 
What  is  constantly  dominant  in  the  idea  of  the  self 
is  the  impression  that  others  have.  One  holds  one's 
self  at  the  estimate  others  have  or  are  imagined  to 
have. 

The  Self  a  Concept.  —  For  psychology,  the  notion  of 
the  self  is  a  concept  similar  in  origin  and  development 
to  any  other.  The  elements  about  which  the  concept 
centres  are  the  organic  and  other  persistent  sensations. 
These  elements  are  closely  connected  with  the  original 
egoistic  instincts  and  receive  constant  additions  by  the 
development  of  new  ideas  and  new  habits.  The  concept 
probably  always  represents  activities  rather  than  mental 
states.  In  its  developed  form  it  is  the  representative 
in  thought  of  the  continuity  of  consciousness,  of  the 
fact  that  the  different  experiences  all  belong  to  the 
same  individual,  and  that  the  acts  of  the  individual  are 
consistent  at  all  times.  The  occasion  for  the  develop- 
ment of  the  concept  is  largely  social,  as  the  need  for 
the  idea  is  social.  Society  must  know  to  what  extent 
an  individual  is  to  be  relied  upon  and  how  he  will  act 
in  all  respects  in  any  set  of  circumstances.  The  self  is 
society's  way  of  formulating  this  knowledge.  It  is  im- 
portant, too,  that  the  individual  should  know  how  he  is 


THE   SELF 


357 


regarded,  and  for  his  own  benefit  should  know  what  he 
is  likely  to  do  in  any  situation.  These  needs  have  led 
to  the  development  of  the  notion  of  the  self  with  all 
that  it  implies. 

Thus  for  psychology  the  self  is  a  concept  to  be  traced 
to  its  sources,  —  is  one  phenomenon  among  others  to  be 
explained  as  best  we  may,  but  such  a  treatment  will 
never  be  satisfactory  for  any  one  else.  What  for  the 
psychologist  is  just  one  problem  on  the  same  level  as  any 
other,  is  for  the  layman  or  for  any  one  in  a  non-psycho- 
logical attitude  the  very  core  of  his  being.  From  it  ir- 
radiate all  desires,  its  advancement  is  the  goal  of  all 
egoistic  instincts,  it  is  the  centre  of  nearly  all  our  joys 
and  sorrows.  To  it  are  referred  all  of  our  purposes  in 
life,  its  exaltation  is  the  object  of  most  of  our  activity. 
All  social  and  physical  events  are  measured  by  their 
effects  on  our  personal  ambition  and  personal  welfare. 
As  the  occasion  of  solicitude  in  all  of  our  social  and 
religious  aspirations,  the  self  takes  on  a  value  that  makes 
any  scientific  analysis  seem  entirely  inadequate  and  even 
presumptuous.  The  treatment  of  the  psychologist  grows 
out  of  his  peculiar  methods  and  needs,  and  much  still 
remains  to  be  done  even  to  attain  his  end  in  his  own  way. 
The  answers  it  gives  must  be  unsatisfactory  to  the  popu- 
lar mind,  for  the  problems  that  most  interest  it  lie  far 
afield  for  the  psychologist.  They  can  be  approached  to 
advantage  only  by  the  methods  and  on  the  assumptions 
of  ethics,  metaphysics,  and  religion.  On  these  problems 
psychology  has  nothing  to  say,  since  the  limitations  of 
its  methods  and  its  knowledge  give  it  no  right  to  an 
opinion. 


358          ESSENTIALS  OF  PSYCHOLOGY 


REFERENCES 

JAMES  :  Principles  of  Psychology,  vol.  i,  chs.  ix  and  x. 
COOLEY  :  Human  Nature  and  the  Social  Order. 
ANGELL:  Psychology,  ch.  xxiii. 
PRINCE  :  The  Dissociation  of  a  Personality. 
MOLL:  Hypnotism. 


INDEX 


Abnormal  psychology,  14. 
Accommodation  in  the   perception  of 

depth,  1 66. 
Action,  284-314. 
Affection,  263. 
After-images,  91  f 
Agraphia,  41. 
Alexia,  41. 
Analysis,  106  f. 
Angell,  F.,  338. 
Angell,  J.  R.,  59, 103, 129, 155, 187,  237, 

271,308,314,342,358. 
Aphasia,  39  f. 
Aristotle,  131,  137. 
Association,  a  form  of  habit,  58  f. 

control  of,  141-146. 

in  perception,  160  ff. 

laws  of,  136-145. 
Association  areas,  39. 
Attention,  104-129. 

and  association,  141  f. 

conditions  of,  107-117. 

duration  of,  122  f. 

genesis  of,  126  ff. 

nervous  basis  of,  116  f. 

range  of,  1 23  ff . 
Attitude,    a    condition    of    attention, 

112. 

Auditory  perception  of  space,  172  ff. 
Axone,  24  ff. 

sheaths  of,  26. 

Bair,  314. 

Behaviour,  psychology,  science  of,  i  f. 

Belief,  219  f. 

Biological  theory  of  instinct,  241  ff. 

Biology  and  psychology,  10. 

Brain  and  mind,  defects  of,  18. 

Bryan,  294. 


Centrally  aroused  sensations,  qualities 
of,  147-151. 

in  perception,  157  f 
Choice,  304-307. 
Clearness,  105  f. 
Colour  blindness,  92  f. 
Colour  contrast,  93  f. 
Colours,  complementary,  90  f. 

primary,  89  f. 
Concept,  220-228. 

self  as,  356  f. 
Consciousness  and  behaviour,  4. 

and  the  nervous  system,  16  ff. 

definition  of,  5. 
Control   of   ideas,    nervous  basis   of, 

145  ff. 
Convergence,  a  factor  in  the  perception 

of  depth,  167. 
Cooley,  358. 
Coover,  338. 
Cord,  action  of,  31. 

paths  in,  31  f. 
Cortex,  action  of,  35-42. 
Cutaneous  sense-organs,  69. 

Darwin,  278  f. 

Dearborn,  336. 

Deduction,  233  ff. 

Definition  of  psychology,  i  ff. 

Dendrite,  24  ff. 

Depth,  perception  of,  165-171. 

Dewey,  237. 

Dissociated  selves,  351-354. 

Distance,  perception  of,  164  f. 

Donaldson,  45. 

Double  images  in  perception  of  depth, 

167  f. 

Dreams,  328  f. 
Duty,  a  condition  of  attention,  1 14  f. 


359 


36o 


INDEX 


Ear,  structure  of,  75  ff. 

Ebbinghaus,  194  f.,  204. 

Ebert,  336. 

Economics  and  psychology,  n. 

Education,    a   condition  of  attention, 

113  f, 

and  psychology,   12. 
Effort,  117  f. 
Emotion,  272-285. 
Experience,  6. 
Experiment,  7  f. 
Experimental  psychology,  14 
Eye,  structure  of,  83-88. 

Faculty  psychology,  criticism  of,  330- 

335- 

Fatigue,  315-325. 

Fear,  an  illustration  of  instinct,  245. 
Fechner,  13. 
Feeling,  258-271. 

theories  of,  266-270. 
Forgetting,  194-199. 
Freud,  328. 
v.  Frey,  64. 

Gallon,  152. 
Ganglion,  28. 
Grey  matter,  22. 

Habits,  48-59- 

and  instinct,  252  f. 

and  the  self,  346  f. 
Hallucination,  184  f. 
Harter,  294. 

Haze,  influence  of,  on  perception,  169. 
Hearing,  74-82. 

theory  of,  78  ff. 
Heck.  342. 
Helmholtz,  79  f. 
Heredity  and  attention,  115. 
History  in  relation  to  psychology,  n. 
Ho  well,  45,  103. 

Ideals  as  motives,  306  ff . 
Illusion,  general,  183  f. 

visual,  180-183. 
Imagination,  213  f. 
Imitation,  251. 
Impulse  and  emotion,  277  f. 
Inattention,  125  f. 


Induction,  235  f. 
Inference,  232  f. 
Inhibition,  effectual,  197  f. 

generative,  196  f. 

retroactive,  195  f. 
Instinct,  238-257. 

and  emotion,  274  ff. 

and  the  synapse,  239  S. 
Intelligence,  general,  training  of,  339. 
Intensity,    a    condition   of   attention, 

io8f. 

Interest,  117  f. 
Interrelations  of  mental  functions,  330- 

342. 

Introspection,  6  f. 
Introspective  psychology,  14. 

James,  59,  129,  139,  144,  155,  215^  224, 
244,  257,  273,  283,  297,  303,  314, 
335>  345,  349.  358. 

Jastrow,  157,  161,  187,  283. 

Jones,  Ernest,  329. 

Judd,  59,  187,  329,  342. 

Judgment,  229-232. 

Kinaesthetic  sensations,  95  f. 
Kiilpe,  148. 

Lange,  273. 
Learning,  191-194. 
as  selection  of  instinctive  movements, 

289  f. 

Livingstone,  355. 
Local  sign,  163. 

Localisation  of  cortical  functions,  36  ff. 
Locke,  61. 

McDougall,  45,  59. 
Marshall,  271. 
Meaning,  220  ff. 

and  memory  image,  206  f. 
Meissner,  69. 
Memory,  188-213. 

logical,  202-207. 

seat  of,  131-134. 

systems  of,  211  ff . 

training  of,  335  ff. 

type,  150  ff. 
Mental  process,  5  ff. 
Meumann,  195,  215,  336. 


INDEX 


361 


Midbrain,  action  of,  34  f. 

Mind,  and  brain,  relation  of,  46  ff . 

definition  of,  5  f. 
Moll,  358. 
Mood,  281. 

Morgan,  Lloyd,  218,  243,  257. 
Motion,  a  factor  in  perception  of  dis- 
tance, i6g. 

perception  of,  169  f. 
Motor  accompaniments  of  attention, 

118-122. 
Movements,  control  of,  296-302. 

in  perception  of  distance,  164  f. 
Miiller,  Johannes,  62. 
Myers,  103,  329. 

Nervous  impulse,  transmission  of,  26  ff. 
Nervous     system,     development     of, 
17-20. 

divisions  of,  20  ff . 

embryonic  development  of,  22  f. 
Neurones,  23-26. 
Noise,  80  f. 

Observation,  6. 

Offner,  329. 

Organic  sensations,  97. 

Pain,  67  ff. 
Paramnesia,  210  f. 
Perception,  157-187. 

of  time,  174  ff. 
Perspective,  168  f. 
Physiological  psychology,  13. 
Plato,  210. 
Play,  250  f. 
Pleasure  and  displeasure  as  feelings, 

259  f. 

Position,  perception  of,  162  ff. 
Pressure,  67  ff. 
Prince,  358. 
Proof,  233-236. 
Psychophysics,  13. 
Purpose,  a  condition  of  attention,  noff. 

Quain,  45. 

Rational  psychology,  14. 
Reading,  as  illustration  of  perception, 
176-180. 


Reasoning,  216-237. 

stages  of,  229. 
Recall,  135  f.,  199-202. 
Recognition,  207-210. 
Reflex  and  instinct  distinguished,  253 

ff. 

Rest,  best  period  for,  320  f. 
Retention,  133  ff.,  194-198. 
Retina,  function  of,  86-89. 
Royce,  342. 

Seashore,  103,  129,  155,  187. 
Self,  the,  343-358. 
Sensation,  60-103. 

and  feeling,  260  ff. 

development  of,  62  f. 
Sensations,  centrally  aroused,  130  ff. 

of  temperature,  63-67. 
Shadows  in  perception  of  depth,  169  f. 
Sherrington,  51. 
Skill,  acquisition  of,  291-295. 
Sleep,  325-328- 
Smell,  72  ff. 

Social  determinants  of  attention,  114  f. 
Social  instincts,  248  ff. 
Sociology  and  psychology,  n. 
Space,  perception  of,  163-174. 
Specific  energy  of  sensory  organs,  61  f. 
Spencer,  131. 
Stanley,  355- 
Static  sense,  96  f. 
Stereoscopic  illusion  of  depth,  168. 
Stout,  271,  283. 

Superposition,  a  factor  in  depth  percep- 
tion, 169. 
Swift,  292. 
Synapse,  29. 

action  of,  33  f .,  48-54. 
Synthesis,  106  f . 

Taste,  sensations  of,  69-72. 

Temperament,  281  ff. 

Tennyson,  349. 

Thorndike,  314. 

Titchener,  59,  103,  129,  155,  187,  215, 

237,  271,  283. 
Training,  transfer  of,  331. 
Trial  and  error  in  the  development  of 

perception,  158  ff. 
as  method  of  learning,  287. 


INDEX 


Visual  sensations,  82-95. 

Watt,  215. 
Weber's  law,  99  ff. 
Weissmann,  241. 


Will,  304-312. 

Work  and  fatigue,  315-325. 

Wundt,  13,  139,  216. 

Zwaardemaker,  74. 


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Attention 


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